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HORSES'  TEETH 


A  TREATISE  ON  THEIR 


MODE   OF   DEVELOPMENT,    ANATOMY, 
MICROSCOPY,  PATHOLOGY,  AND  DENTISTRY  ;    COMPARED   WITH 
THE    TEETH   OF    MANY   OTHER    LAND    AND    MARINE 
ANIMALS,     BOTH     LIVING      AND     EXTINCT  ; 
WITH   A   VOCABULARY    AND   COPI- 
OUS    EXTRACTS     FROM 
THE   WORKS   OP 


ODONTOLOGISTS  AND  VETERINARIANS. 


WILLIAM   H.  CLARKE. 


SECOND      EDITION,      REVISED, 


Horses  have  very  nearly  the  same  diseases  as  men.— Pliny. 
We  ought  to  make  not  merely  books,  but  valuable  collections,  and  to 
acknowledge  the  sources  whence  we  derive  assistance. — Ibid. 


NEW  YORK : 

WILLIAM  R.  JENKINS, 

veterinary  publisher  and  bookseller, 

850  Sixth  Avenue. 

1884. 


Copyright,  1879,  by  William  H.  ClabkEo 


Smith  &  McDougal,  Electrotypees, 
82  Beekraan  St.,  N.  Y. 


PREFACE 


THE  favorable  reception  of  the  first  edition  of  this 
work  by  both  press  and  public  and  my  desire 
to  encourage  the  study  of  Veterinary  Science  and 
Comparative  Anatomy  are  the  chief  reasons  for  a 
Revised  Edition.  The  improvements  consist  in  an 
Ai^pendix,  numerous  Illustrations,  a  new  Index,  and 
the  correction  of  errors  in  and  the  addition  of  fresh 
matter  to  the  text  and  vocabulary. 

I  am  indebted  to  Mr.  Jacob  L.  Wortman  of  Phil- 
adelphia for  the  able  article  on  fossil  horses  in  the 
Appendix,  and  to  Prof.  E.  D.  Cope,  editor  of  The 
American  Naturalist^  for  a  careful  revision  and  im- 
provement of  it.  Some  of  the  reference  notes,  how- 
ever, are  my  own. 

It  was  not  my  intention  originally  to  make  the  book 
an  exponent  of  the  Doctrine  of  Evolution.  The  dis- 
cussion of  the  subject,  however,  is  justifiable,  for  a 
work  that  does  not  embrace  all  the.  facts  science 
furnishes  is  unworthy  of  the  age,  and  to  shirk  the  re- 
sponsibility of  the  discussion  because  the  subject  is 
unpopular  is  cowardly.  The  fact  that  fossil  horses' 
teeth  are  inseparably  connected  with  those  of  the 
modern  horse  renders  their  consideration  unavoidable. 
Further,  in  addition  to  being  one  of  the  most  impor- 
tant factors  Paleontology  has  thus  far  furnished  in 


IV  PREFACE. 

elucidating  the  subject  of  Evolution,  they  give  in- 
creased scope  and  importance  to  the  book  itself. 
Truly  the  late  Dr.  John  W.  Draper  was  right  when, 
at  a  mere  glance,  he  said:  ^'The  subject  (horses' 
teeth)  is  so  suggestive  !" 

So  far  as  Evolution  is  concerned,  I  can  only  repeat 
what  I  said  in  the  first  Preface,  namely,  that  it  denotes 
improvement,  and  that  Nature's  laws  are  immutable, 
and  to  oppose  them  is  as  foolish  as  to  beat  the  head 
against  a  stone  wall. 

Again,  as  said  in  the  first  Preface,  I  think  I  can  say 
now  from  experience  that  Special  Works,  on  account 
of  the  thoroughness  with  which  they  are  usually  pre- 
pared, are  growing  in  public  favor  (an  opinion  in 
which  so  able  a  journal  as  The  Syracuse  (N.  Y.) 
Standard  concurs),  and  that  while  General  Works 
have  their  advantages,  thoroughness  of  detail  is  not 
usually  among  them. 

W.  H.  C. 

New  York,  September,  1883. 


CONTENTS 


FAGS 

INTRODUCTION.— Fundamental  Principles  of  Dental  Science 7 

CHAPTER    I. 

TOOTH-GERMS   (ODONTOGENY). 

Periods  at  which  the  Germs  are  visible  in  the  Fetus.— Dentine  and 
Enamel  Germs.— A  Cement  Germ  in  the  Foal.— The  Horse's  Upper 
Grinders  said  to  be  developed  from  Five  Germs,  the  Lower  from 
Four.— Similar  development  of  the  Human  Teeth.— Monsieur  Mag- 
itot's  Researches 31 

CHAPTER    n. 

THE   TEMPORARY   DENTITION, 

Twelve  Incisors  and  Twelve  Molars.— Why  the  Incisors  are  calle 
"Nippers." — The    Treatment    of  Foals  Affects  Teething.— Roots 
of  Milli  Teeth  Absorbed  by  the  Permanent.- The  Tushes 47 

CHAPTER    III. 

THE  PERMANENT   DENTITION. 

Distinction  between  Premolars  and  Molars. -The  Bow-like  Incisors.— 
Contrasts  between  the  Ui)per  and  Lower  Grinders,  and  the  Rows 
formed  by  them.  — The  Incisors  saved  from  Friction. — Horses' 
Teeth  compared  with  those  of  other  Animals.— Measurements.— 
Time's  Changes. — Growth  during  Life 53 

CHAPTER     IV. 

THE  CANINE    TEETH   OR   TUSHES. 

Practically  Useless.— Different  in  their  Nature  from  the  other  Teeth.— 
Were  "they  formerly  Weapons  of  Offense  and  Defense  j— "Views  of 
Messrs.  Darwin.  Hunter.  Bell,  Youatt,  and  Winter.— Their  time  of 
Cutting  the  most  Critical  Period  of  the  Horse's  Life 75 

CHAPTER    V. 

THE  REilNANT  TEETH. 
Usuallv  regarded  as  Phenomenons.— The  Name.— Traced  to  the  Fossil 
Horses,  in  which  (in  the  Pliocene  Period)  they  "Cea-^ed  tobeFnnc- 
tionaliy  Developed.''— Nntnre's  Metamorphoses — "The  Agencies 
which  "are  at  work  in  Modeling  .\nimal  and  Vegetable  Forms." — 
Why  Remnant  Teeth  are  often  as  it  were.  Prematurely  Lost.— Fos- 
sil Horses  and  a  Fossil  Toothed-Bird 94 


Yl  CONTENTS. 

CHAPTER    VI. 

DENTAL   CYSTS  AND   SUPERNUMERARY   TEETH.  page 

Teeth  growiu":  in  various  parts  of  the  Bod3^ — Some  Cysts  more  Prolific 
thau  others,  Producin-i;  a  Second,  if  not  a  Third,  "Dentition/'— 
Reports  and  Theories  of  Scientiiic  Men.— Cases  ol  Thud  Dentition 
in  Human  Beings 115 

CHAPTER    Vn. 
horses'  teeth  under  the  microscope. 

The  Dentinal  Tabes,  Enamel  Fibers,  and  Cemental  Canals  Described 
and  Contrasted 130 

CHAPTER    VUI. 

THE  PATHOLOGY  OP  THE  TEETH. 

Iraportancs  of  the  Subject.— Caries  caused  by  Inflamed  Pulps,  Blows, 
•\irus,  and  Morbid  Diathesi:;.— Supernumerary  Teeth  and  other 
Derangements.— Trephinrng  the  Sinuses.  -  Gutta  Percha  as  a  Fill- 
ing.— Cleaning  the  Teeth.— "A  Diseased  Fossil  Tooth 136 

CHAPTER     IX. 

THE  DENTISTRY  OF  THE  TEETH. 

Reports  of  Cases  Treated  by  Various  Surgeons.— Gutta  Percha. as  a 
Filling  for  Trephined  Sinuses.— Teeth  Pressing  against  the  Palate. 
— Pas.-ing  a  Probe  through  a  Decayed  Tooth.— Death  of  a  Horse 
from  S\\  allowing  a  Diseased  Tooth ITS 

CHAPTER     X. 

FRACTURED     JAWS. 

How  Caused,  and  how  to  Distinguish  an  Abrasion  of  the  Gums  from  a 
Fracture  of  the  Bone. — Replacing  an  Eye,  Amputating  part  of  a 
Lower  Jaw,  taking  a  Fractured  Tooth  and  Bones  out  through  the 
Nostril,  &c ; 194 

CHAPTER    XI. 

THE   TEETH   AS    INDICATORS   OF   AGE. 
Their  various  ways  of  Indicating  Age.— The  '•  Mark's  "  Twofold  Use.— 
The  Dentinal  Star.— MarivS  with  too  much  Cement.— Tricks  of  the 
Trade.— Crib-biting.— Signs  of  Ago  Independent  of  the  Teeth 203 

CHAPTER     XII. 

THE   TRIGEMINUS    OR   FIFTH   PAIR   OF   NERYES. 
Its  Nature  and  the  Relation  it  bears  to  the  Teeth.— Its  Course  in  the 
Horse  and  in  Man 216 

VOCABULARY 227 

APPENDIX.— Rec(mt  Discoveries  of  Fossil  Horses.— Views  of  an  Evo- 
lutionist.—Oriiriual  Home  of  the  Horse.— Elephant  Tooth-Gernas.- 
Filling  Children's  Teeth 257 

INDEX 279 

PUBLIC  OPINION 387 


USTTEODUCTION". 


The  following  matter,  which  is  designed  to  give  at 
least  a  synopsis  of  the  fundamental  principles  of  dental 
science,  is  compiled  from  the  works  of  the  best  known 
odontologists.  It  is  somewliat  heterogeneous  in  its 
make-up,  and  is,  moreover,  considering  that  it  is  an 
Introduction  to  a  special  work,  anomalous,  being 
rather  an  adjunct  to  than  an  ex2:>lanation  of  the  work 
itself.  Its  lack  of  coherency  and  the  few  repetitions, 
the  inevitable  concomitants  of  all  compilations,  are 
offset  by  the  interest  of  its  historical  records  and  the 
scope  and  clearness  of  its  thoughts  and  deductions. 
While  it  does  not  treat  specially  of  horses'  teeth,  it  is 
just  as  applicable  to  them  as  to  human  teeth,  or  to 
those  of  any  of  the  other  animals  mentioned.  It  is 
believed  that  the  student  of  dental  science  will  find 
the  matter  as  useful  as  it  is  interesting:. 

In  his  work  entitled  "The  Anatomy  of  Vertebrates" 
(vol.  i,  pp.  357-8),  Prof.  Richard  Owen  says: 

"A  tooth  is  a  hard  body  attached  to  the  mouth  or 
beginning  of  the  alimentary  canal,  partially  exposed, 
when  developed.  Calcified  teeth  are  peculiar  to  the 
vertebrates,  and  may  be  defined  as  bodies  primarily,  if 
not  permanently,  distinct  from  the  skeleton,  consisting 


vm  IXTRODUCTIOIS'. 

of  a  cellular  and  tubular  basis  of  animal  matter,  con- 
taining earthy  particles,  a  fluid,  and  a  vascular  pulp. 

'^In  general,  the  earth  is  present  in  such  quantity 
as  to  render  the  tooth  harder  than  bone,  in  which  case 
the  animal  basis  is  gelatinous,  as  in  other  hard  parts 
where  a  great  proportion  of  earth  is  combined  with 
animal  matter.  In  a  very  few  instances,  among  the 
vertebrate  animals,  the  hardening  material  exists  in  a 
much  smaller  proportion,  and  the  animal  basis  is  albu- 
minous ;  the  teeth  here  agree,  in  both  chemical  and 
physical  qualities,  with  bone. 

"I  propose  to  call  the  substance  which  forms  the 
main  part  of  all  teeth  dentine.*  The  second  tissue, 
whicli  is  the  most  exterior  in  situation,  is  the  cement. 
The  third  tissue,  wliich,  when  present,  is  situated  be- 
tween the  dentine  and  cement,  is  the  enamel. 

"Dentine  consists  of  an  organized  animal  basis  and 
of  earthy  particles.     The  basis  is  disposed  in  the  form 

*In  a  reference  note  in  the  Introduction  to  liis  "Odontogra- 
phy," Prof.  Owen  says:  "Besides  the  advantag-e  of  a  substan- 
tive for  an  unquestionably  distinct  tissue  under  all  its  modifica- 
tions in  tlie  animal  kingdom,  the  term  dentine  may  be  inflected 
adjectively,  and  the  properties  of  this  tissue  described  without 
the  necessity  of  periphrasis.  Thus  we  may.speak  of  the  '  denti- 
Dal'  pulp,  'dentinal'  tubes  or  cells,  as  distinct  from  the  corre- 
sponding properties  of  the  other  constituents  of  a  tooth.  The 
term  'dental'  will  retain  its  ordinary  sense,  as  relating  to  the 
entire  tooth  or  system  of  teeth." 

Wote.—  The  particular  paraprraph  to  which  the  aVove  note  re- 
fers is  from  Prof.  Owen's  "  Odontography."  "  The  Anatomy  of 
Vertebrates  "  having  been  written  about  twenty-five  years  sub- 
sequent to  the  "Odontography,"  and  therefore  reflecting  the 
Professor's  riper  thon2:hts,  the  extracts  made  from,  it  were  sub- 
Btituted  for  very  similar  matter  in  the  "  Odontography." 


TL'BES   WITH    XOrRISIIIXG,    COIOKLLSS    FLUID.      IX 

of  compartments  or  cells,  and  extremely  minute  tubes. 
The  earthy  particles  have  a  twoibld  arrangement,  be- 
ing either  blended  with  the  animal  matter  of  the  in- 
terspaces and  parietes  of  the  tubes,  or  contained  in  a 
minute  granular  state  in  their  cavities.  The  density 
of  the  dentine  arises  principally  from  the  proportion 
of  earth  in  the  first  of  these  states  of  combination. 
The  tubes  contain,  near  the  formative  pulp,  filament- 
ary processes  of  that  part,  and  convey  a  colorless  fluid, 
probably  transuded  'j^^^sma.'  They  thus  relate  not 
only  to  the  mechanical  conditions  of  the  tooth,  but  to 
the  vitality  and  nutrition  of  the  dentine.  This  tissue 
has  few  or  no  canals  large  enough  to  admit  capillary 
vessels  with  the  red  particles  of  blood,  and  it  has  been 
therefore  called  'unvascular  dentine.' 

*'  Cement  always  closely  corresponds  in  texture  with 
the  osseous  tissue  of  the  same  animal ;  and  whenever 
it  occurs  of  different  thickness,  as  upon  the  teeth  of 
the  horse,  sloth,  or  ruminant,  it  is  also  traversed,  like 
bone,  by  vascular  canals.  When  tiie  osseous  tissue  is 
excavated,  as  in  dentigerous  vertebrates  above  fishes, 
by  minute  radiated  cells,  forming,  with  their  contents, 
the  ^  corpuscles  of  Purkinje,'  these  are  likewise  present, 
of  similar  size  and  form,  in  the  cement,  and  are  its 
chief  characteristic  as  a  constituent  of  the  tooth.  The 
hardening  material  of  the  cement  is  partly  segregated 
and  combined  with  the  parietes  of  the  radiated  cells 
and  canals,  and  is  partly  contained  in  disgregated 
granules  in  the  cells,  which  are  thus  rendered  white 
and  opaqne,  viewed  by  reflected  light.  The  relative 
density  of  the  dentine  and  cement  varies  according  to 
the  proportion  of  the  earthy  material,  and  chiefly  of 
that  part  which  is  combined  with  the  animal  matter 
in  the  walls  of  the  cavities,  as  compared  with  the  size 


X  IKTKODUCTIO^'. 

and  number  of  the  cavities  themselves.  In  the  complex 
grinders  of  the  elephant,  the  masked  boar,  and  the 
copybara,  the  cement,  which  forms  nearly  half  the 
mass  of  the  tooth,  wears  down  sooner  than  the  dentine, 
"  The  enamel  is  the  hardest  constituent  of  a  tooth, 
and,  consequently,  the  hardest  of  animal  tissues;  but 
it  consists,  like  the  other  dencal  substances,  of  earthy 
matter  arranged  by  organic  forces  in  an  animal  matrix. 
Here,  however,  the  earth  is  mainly  contained  in  the 
canals  of  the  animal  membrane,  and,  in  mammals  and 
reptiles,  completely  fills  those  canals,  which  are  com- 
paratively wide,  whilst  their  parietes  are  of  extreme 
tenuity.  The  hardening  salts  of  the  enamel  are  not 
only  present  in  far  greater  proportion  than  in  the  den- 
tine and  cement,  but,  in  some  animals,  are  peculiarly 
distinguished  by  the  presence  of  the  fiuate  of  lime." 

Again  Prof.  Owen  says  ("  Anat.  of  Yert/^  voL  i,  pp> 
359-60) ; 

^*  Teeth  vary  in  number,  size,  form,  sfructtire,  modi- 
fications of  tissue,  position,  and  mode  of  attachment 
in  different  aninialg.  They  are  principally  adapted  for 
seizing,  tearing,  dividing,  pounding,  or  grinding  the 
food.  In  same  animals  they  are  modified  to  serve  as 
weapons  of  offense  and  defense;  in  others,  as  aids  in 
locomotion,  means  of  anchorage,  instruments  for  up- 
rooting or  cutting  down  trees,  or  for  transport  and 
working  of  building  materials.  They  are  characteristic 
of  age  and  sex,  and  in  man  they  have  secondary  rela- 
tions subservient  to  beauty  and  to  speech. 

"Teeth  are  always  most  intimately  related  to  the 
food  and  habits  of  the  animal,,  and  are  therefore  highly 


LOST   DURABLE    OF   AXIMAL   SL'BSTAXCES.  XI 

interesting  to  the  physiologist.  They  form  for  the 
same  reason  most  important  guides  for  the  naturalist 
in  the  classification  of  animals;  and  their  value,  as 
zoological  characters,  is  enhanced  by  the  facihty  with 
which,  from  their  position,  they  can  be  examined  in 
living  or  recent  animals.  The  durability  of  their  tis- 
sues renders  them  not  less  available  to  the  paleontolo- 
gist in  the  determination  of  the  nature  and  affinities 
of  extinct  species,  of  whose  organization  they  are  often 
the  sole  remains  discoverable  in  the  deposits  of  former 
pen'ods  of  the  earth's  history." 

Prof.  A.  Chanveau  says  ("Comparative  Anatomy  of 
the  Domesticated  Animals"): 

"  Identical  in  all  our  domesticated  animals  by  their 
general  disposition,  mode  of  development,  and  struc- 
ture, in  their  external  conformation  the  teeth  present 
notable  differences,  the  study  of  which  offers  the 
greatest  interest  to  the  naturalist.  For  it  is  on  the 
form  of  its  teeth  that  an  animal  depends  for  its  mode 
of  alimentatioii;  it  is  the  regime,  in  its  turn,  which 
dominates  the  instincts,  and  commands  the  diverse 
modifications  in  the  apparatus  of  the  economy;  and 
there  results  from  this  law  of  harmony  so  striking  a 
correlation  between  the  arrangement  of  the  teeth  and 
the  conformation  of  the  other  organs,  that  an  anato- 
mist may  truly  say,  'Give  me  the  tooth  of  an  animal, 
and  I  will  tell  you  its  habits  and  structure.'" 

In  a  letter  which  I  wrote  to  Prof.  Theodore  Gill,  of 
the  Smithsonian  Institution,  Washington,  D.  C.,  I 
asked  what  there  was  about  teeth  that  enabled  natu- 
ralists to  tell  so  much  bv  them.     In  reply  he  said: 


Xll  INTRODUCTION. 

*'  The  teeth  are  quite  constant  in  the  same  type,  are 
generally  appreciably  modified  according  to  family,  are 
the  most  readily  preserved  in  a  fossil  state,  and  are  in 
direct  relation  with  the  economy  of  the  animal.  Hence 
they  furnish  the  best  indications  of  the  relations  of 
the  animal  to  wliich  they  belonged,  especially  in  cases 
Avhere  the  type  was  not  very  different  from  an  existing 
one.  In  the  case  of  the  older  and  more  aberrant  types, 
however,  the  indications  furnished  by  the  dentition 
should  be  iiccepted  with  great  caution." 

In  the  Introduction  to  his  •'  Odontography "  Prof. 
Owen  gives,  besides  his  own  and  other  men's  views,  a 
history  "of  the  leading  steps  to  the  present  knowl- 
edge" of  dental  science  (that  is,  up  to  1844),  of  which 
the  following  are  extracts : 

"  As  regards  the  teeth,  the  principle  of  chief  import 
to  the  physiologist  arises  out  of  the  fact,  which'  has 
been  estabhshed.  by  microscopic  investigations,  that  the 
earthy  particles  of  dentine  are  not  confusedly  blended 
with  the  animal  basis,  and  the  substance  arranged  in 
superimposed  layers,  but  that  these  particles  are  built 
up  with  the  animal  basis  as  a  cement,  in  the  form  of 
tubes  or  hollow  columns,  in  the  predetermined  arrange- 
ment of  which  there  may  be  discerned  the  same  rela- 
tion to  the  acquisition  of  strength  and  power  of  resist- 
ance in  the  due  direction,  as  in  the  disposition  of  the 
columns  and  beams  of  a  work  of  human  architecture. 

"  Whoever  attentively  observes  a  polished  section  or 
a  fractured  surface  of  a  human  tooth  may  learn,  even 
with  the  naked  eye,  that  the  silky  and  iridescent  luster 
reflected  fr.im  it  in  certain  directions  is  due  to  the 
presence  of  a  fine  fibrous  structure. 


EARLY    MICROSCOPICAL   DISCOVEEIES.  Xlll 

"  Malpighi,*  in  whose  works  may  be  detected  the 
germs  of  many  important  anatomical  truths  that  have 
subsequently  been  matured  and  estabhshed,  says  the 
teeth  consist  of  two  parts,  of  which  the  internal  bony 
layers  (dentine)  seem  to  be  composed  of  fibrous  and,  as 
it  were,  tendinous  capillaments  reticularly  interwoven. 

"Leeuwenhoek,f  having  applied  his  microscopical 
observations  to  the  structure  of  the  teeth,  discovered 
that  the  apparent  fibers  were  really  tubes,  and  he  com- 
municated a  brief  but  succinct  account  of  his  discovery 
to  the  Eoyal  Society  of  London,  which  was  published, 
together  with  a  figure  of  the  tubes,  in  No.  140  of  their 
Transactions.  This  figure  of  the  dentinal  tubes,  with 
additional  observations,  again  appeared  in  the  Latin 
edition  of  Leeuwenhoek's  works,  published  at  Leyden 
in  1730.  The  dentine  of  the  human  teeth,  and  also 
that  of  young  hogs,  is  described  as  being  'formed  of 
tubuli  spreading  from  the  cavity  in  the  center  to  the 
circumference/  He  computed  that  he  saw  a  hundred 
and  twenty  of  the  tubuli  within  the  forty-fifth  part  of 
an  inch.  He  was  aware  also  of  the  peculiar  substance 
now  termed  the  cement,  or  crusta  jMrosa,  which  enters 
into  the  composition  of  the  teeth  of  the  horse  and  the 
ox. 

"These  discoveries  may  be  said  to  have  appeared 
before  their  time.     The  contemporaries  of  Leeuwen- 

*  An  Italian  physician  ;  born  in  1628  ;  died  in  1604.  He  was 
the  first  to  apply  the  newly-invented  microscope  in  the  study  of 
anatomy. 

X  A  Dutch  naturalist  and  manufacturer  of  optical  instruments. 
His  microscopes  were  said  to  be  the  best  in  Europe.  Besides 
his  dental  discoveries,  he  discovered  the  red  globules  of  the 
blood,  the  infusorial  animaVules,  and  that  of  the  spermatozoa. 
Born  in  Delft  October  24,  1G32;  died  there  August  26,  1723. 


XIT  IXTRODUCTIOX. 

hoek  were  not  prepared  to  appreciate  them ;  besides 
they  could  neither  repeat  nor  confirm  them,  for  his 
means  of  observation  were  pecuharly  his  own;  and 
hence  it  has  happened  that,  with  the  exception  of  the 
learned  Portal,*  they  have  either  escaped  notice,  or 
have  been  designedly  rejected  by  all  anatomists  until 
the  time  of  the  confirmation  of  their  exactness  and 
truth  by  Purkinje  in  1835." 

Continuing  tlie  subject,  Prof.  O'ven  further  says  of 
the  three  constituent  parts  of  teeth— dentine,  enamel, 
and  cement — beginning  with 

THE   DEK-TIK-E. 

^•Purldnje  states  that  the  dentine  consists,  not  of 
superimposed  layers,  but  of  fibers  arranged  in  a  homo- 
geneous intermediate  tissue,  parallel  with  one  another, 
and  perpendicular  to  the  surface  of  the  tooth,  running 
in  a  somewhat  wavy  course  from  the  internal  to  the 
external  surface,  and  he  believed  these  fibers  to  be 
really  tubular,  because  on  bringing  ink  into  contact 
with  them,  it  was  drawn  in  as  if  by  capillary  attraction. 

"  On  the  publication  of  this  discovery,  it  was  imme- 
diately put  to  the  test  by  Prof.  Miiller,  by  whom  the 
tubular  structure  of  the  denthie  was  not  only  con- 
firmed, but  the  nature  and  one  of  the  offices  of  the 
tubes  were  determined.  He  observed  that  the  white 
color  of  a  tooth  was  confined  to  these  tubes,  which  were 
imbedded  in  a  semitransparent  substance,  and  he  found 
that  the  whiteness  and  opacity  of  the  tubes  were  re- 
moved by  acids.  On  breaking  a  thin  lamella  of  a  tooth 
transversely  with  regard  to  its  fibers,  and  examining 
the  edge  of  the  fracture,  Miiller  perceived  tubes  pro- 

*  "  Histoire  de  I'Anatomie  et  de  la  Cliirurgie,"  Paris,  1770. 


WHAT  THE  TUDr.S  COXTAl^T.  XV 

jecting  here  and  there  from  the  surfaces.  They  were 
white  and  opaque,  stiff,  straight,  and  apparently  not 
flexible.  This  appearance  is  well  reprosecuted  in  the 
old  figure  by  Leeuwenhook.  If  the  lamellse  had  been 
previously  acted  upon  by  acid,  the  projecting  tubes 
were  flexible  and  transparent,  and  often  very  long. 
Hence  Miiller  inferred  that  the  tubes  have  distinct 
walls,  consisting  of  an  animal  tissue,  and  tiiat,  besides 
containing  earthy  matter  in  their  interior,  their  tissue 
is,  in  the  natural  state,  impregnated  with  calcareous 
salts."* 

THE  CEMEKT. 

"The  organised  structure  and  microscopic  character 
of  the  cement  were  first  determined  by  Purkinje  and 
Faenkel,  and  the  acquisition  of  these  facts  led  to  the 
detection  of  the  tissue  in  the  simple  teeth  of  nun  and 
carnivorous  animals.  The  cement  is  most  conspicuous 
where  it  invests  the  root  of  the  tooth,  and  increases  m 
thickness  as  it  approaches  the  apex  of  the  root.  The 
animal  constituent  of  this  part  of  the  cement  had  been 
recognised  by  Berzelius  as  a  distinct  investment  of  the 
dentine  long  before  the  tissue  of  which  it  formed  the 
basis  was  clearly  recognized  in  simple  teeth.  Berzelius 
describes  the  cemenlal  membrane  as  being  less  consist- 
ent than  the  animal  basis  of  the  dentine,  but  resisting 

"  If  Lord  Bacon's  theory  is  correct,  the  probability  is  that  these 
tubes  contain  something  besides  earthy  matter  and  calcareous 
salts,  to  wit  spirit.  In  "Novum  Organum"  he  says  (B.  Mou- 
tagu,  vol.  xiv,  p.  417):  "All  things  abhor  a  solution  of  their 
continuity,  but  yet  in  .proportion  to  their  rarity.  The  more  rare 
the  bodies  be,  the  more  they  suffer  themselves  to  be  thrust  into 
small  and  narrow  passaiTes ;  for  Avater  will  go  into  a  passage 
which  dust  wiH  not  go  into,  air  which  water  will  not  go  into, 
and  flame  and  spirit  which  air  will  not  go  into." 


Xvi  IXTEODL'CTIOX. 

longer  the  solvent  action  of  boiling  water,  and  retain- 
ing some  fine  particles  of  the  earthy  phosphates  when 
all  such  earth  liad  been  extracted  from  the  dentinal 
tissue.  Cuvier  also  states  that  the  cement  is  dissolved 
with  more  difficulty  in  acid  than  the  other  dental  tis- 
sues. Retzius,*  however,  states  that  the  earth  is 
sooner  extracted  by  acid  from  the  cement  than  from 
the  dentine  of  the  teeth  of  the  horse. 

^•In  recent  mammalian  cement  the  radiated  cells,  like 
the  dentinal  tubes,  owe  their  whiteness  and  opacity  to 
the  earth  whicli  they  contain.  According  to  Retzius, 
'numerous  tubes  radiate  from  the  cells,  which,  being 
dilated  at  their  point  of  beginning,  give  the  cells  the 
appearance  of  an  irregular  star.  These  tubes  form 
numerous  combinations  with  each  other,  partly  direct 
and  partly  by  means  of  fine  branches  of  TTtoo^^^  ^^ 
Toooo^^i  of  an  inch  in  diameter.  The  cells  vary  in 
size.  The  average  size  of  the  Purkinjean  cells  in  hu- 
man cement  is  y-g-Vo^^^  ^^'  ^^^  inch.  In  sections  made 
transversely  to  the  axis  of  the  tooth,  it  is  clearly  seen 
that  these  cells  are  arranged  in  parallel  or  concentric 
striae,  of  which  «ome  are  more  clearly  and  others  more 
faintly  visible,  as  if  the  cement  were  deposited  in  fine 
and  coherent  layers.'     The  layer  of  cement  is  found  in 

*Prof  Retzius,  of  the  University  of  Stockholm,  informs  us 
that  he  had  been  led  by  the  iridescence  of  the  fractured  surface 
of  the  substance  of  a  tooth  to  conceive  that  that  appearance  was 
due,  as  in  the  crystalline  lens,  to  a  fine  fibrous  structure,  and  that 
he  communicated  his  o|)inions  as  to  the  regular  arran^rement  of 
these  fibers  to  some  of  his  colleagues  in  1834.  In  18o5,  havino- 
obtained  a  powerful  microscope,  he  began  a  series  of  more  exact 
researches  on  the  intimate  structure  of  the  teeth  in  man  and 
the  lower  animals,  which  he  communicated  to  the  Royal  Acad- 
emy of  Sciences  at  Stockholm  on  January  13,  1836,  being  then 
unacquainted  with  the  discoveries  of  Purkinje. — Owen. 


EXOSTOSIS   OF  THE    ROOT.  xvii 

the  deciduous  teetli,  but  is  relatively  thinner,  and  the 
Purkinjean  cells  are  more  irregular. 

"*In  growing  teeth,  with  roots  not  fully  formed, 
the  cement  is  so  thin  that  the  Purkinjean  cells  are 
not  visible.  It  looks  like  a  fine  membrane,  and  has 
been  described  as  the  periosteum  of  the  roots,  which 
are  wholly  composed  of  it ;  but  it  increases  in  thick- 
ness with  the  age  of  the  tooth,  and  is  the  seat  and  ori- 
gin of  what  are  called  exostoses  of  the  roots.'  These 
growths  are  subject  to  the  formation  of  abscesses,  and 
all  the  morbid  actions  of  true  bone. 

"It  is  the  presence  of  this  osseous  snbstance  which 
renders  intelhgible  many  well-known  experiments  of 
which  human  teeth  have  been  the  subjects,  such  as 
their  transplantation  and  adhesion  into  the  combs  of 
cocks,  and  the  establishment  of  a  vascular  connection 
between  the  tooth  and  the  comb. 

"Under  every  modification  the  cement  is  the  most 
■highly  organized  and  most  vascular  of  the  dental  tis- 
sues, and  its  chief  use  is  to  form  the  bond  of  vital 
union  between  the  denser  and  commonly  unvascular 
constituents  of  the  tooth  and  the  bone  in  w'hich  the 
tooth  is  implanted.  In  a  few  reptiles  (now  extinct), 
and  in  the  herbivorous  mammalia,  the  cement  not  only 
invests  the  exterior  of  the  teeth,  but  penetrates  their 
substance  in  vertical  folds,  varying  in  number,  form, 
extent,  thickness,  and  degree  of  complexity,  and  con- 
tributing to  maintain  that  inequality  of  the  grinding 
surface  of  the  tooth  which  is  essential  to  its  function 
as  an  instrument  for  the  comminution  of  vegetable 
substances."* 

*  CEivrENT  MisTAKET^r  FOR  Taetak  (Odontot/tthosX — Sur- 
geon E.  May  hew  says  ("The  Horse's  Mouth,"  &c.) :  "Within 
the  alveolar  cavityj  the  crusta  petrosa^  which  becomes  of  con- 


XVm  INTRODUCTION^". 


THE   EKAMEL. 

"The  higher  an  animal  is  placed  in  the  scale  of  or- 
ganization, the  more  distinct  and  characteristic  are  not 
only  the  various  organs  of  the  body,  but  the  different 
tissues  which  enter  into  their  composition.  This  la^v 
is  well  exemplified  in  the  teeth,  although  in  the  com- 
parison of  these  organs  we  are  necessarily  limited  to 
the  range  of  a  single  primary  group  of  animals.  We 
have  seen,  for  example,  that  the  dentine  is  scarcely 
distinguishable  from  the  tissue  of  the  skeleton  in  the 
majority  of  fishes;  but  that  its  peculiarly  dense,  un- 
vascular,  and  resisting  structure,  which  is  the  excep- 
tionable condition  in  fishes,  is  its  prevalent  character 
in  the  teeth  of  the  higlier  vertebrates. 

"So  likewise  with  the  enamel.  This  substance, 
which  under  all  its  conditions  bears  a  close  analogy 
with  the  dentine,  is  hardly  distinguishable  from  that" 
tissue  in  the  teeth  of  many  fishes.  The  fine  calciger- 
ous*  tubes  are  present  in  both  substances,  and  undergo 
similar  subdivisions,  the  directions  only  of  the  trunks 

siderable  tliickness  around  the  root,  is  of  a  yellowish-white 
color ;  but  where,  as  on  the  crown  of  the  tooth,  it  is  exposed  to 
the  chemical  action  of  food  and  air,  it  presents  a  darker  aspect, 
and  resembles  an  accumulation  of  tartar,  for  which  indeed  it 
has  becm  mistaken.  It  fills  up  the  infundibula  of  the  grinders 
and  lines  those  of  the  incisors.  It  is  pierced  by  all  the  vessels 
which  nourish  the  teeth." 

The  editor  of  "The  Veterinarian"  (1849),  in  a  "review"  of 
Mr.  Mayhew's  work,  says:  "  Both  English  and  French  veteri- 
nary writers  have  mistaken  the  crusta  petrosa  for  tartar,  not  be- 
ing" aware  of  its  existence  inside  as  well  as  outside  of  the  tooth." 

*  This  word  is  peculiar  to  if  not  originated  by  Prof  Owen.  It 
is  synonymous  with  the  word  Ca'ciferous  (limy). 


THE    ENAMEL',.;    VARIEGATED    BEAUTIES.  XIX 

and  branches  being  reA'ersed,  agreeably  with  the  con- 
trary course  of  their  respective  developments.  The 
proportion  of  animal  matter  is  also  greater  in  the 
enamel  of  the  teeth  of  fishes  than  in  the  higher  verte- 
brata,  and  the  proportion  of  the  calcareous  salts  incor- 
porated with  the  animal  constituent  of  the  walls  of 
the  tubes  is  greater  as  compared  with  the  subcrystal- 
line  part  deposited  in  the  tubular  cavities. 

"The  enamel  may  be  distinguished,  independently 
of  its  microscopic  and  structural  characters,  by  its 
glistening,  subtransparent  substance,  which  is  wdiite 
or  bluish-white  by  reflected  light,  but  of  a  gray-brown 
color  when  viewed,  under  the  microscope,  by  trans- 
mitted light.  *  ^  *  The  enamel  of  the  molar 
tooth  of  a  calf,  which  has  just  begun  to  appear  above 
the  gum,  and  which  can  readily  be  detached  from  the 
dentine,  especially  near  the  beginning  of  the  roots,  is 
resolvable  into  apparently  fine  prismatic  fibers.  If 
these  fibers  be  separately  treated  with  dilute  muriatic 
acid,  and  the  residue  examined  with  a  moderate  mao-- 
nifying  power,  in  distilled  water,  or,  better,  in  dilute 
alcohol,  portions  of  more  or  less  perfect  membranous 
sheaths  or  tubes  will  be  discerned,  which  inclosed  the 
earthy  matter  of  the  minute  prism,  and  served  as  the 
mold  in  which  it  was  deposited. 

"Prof.  Eetzius,  who  obtained  a  small  portion  of 
organic  or  animal  substance  from  the  enamel-fibers  of 
an  incompletely-formed  tooth  of  a  horse,  conjectured 
that  it  was  a  deposition  of  that  fluid  whicli  originally 
surrounds  the  loose  enamel-fibers,  and  that  *in  pro- 
portion as  these  fibers  are  pressed  tighter  together,  and 
additional  fibers  are  wedged  between  them,  the  organic 
deposition  is  forced  away.' 

"Retzius  accuratelv  describes  the  enamel-fibers  of 


XX  INTRO  DUCTIOX. 

the  horse  as  presenting  the  form,  of  angular  needles, 
about  g-fiVo^^^  of  '^^'^  i^^c^^  ^^^  diameter,  which  are  trav- 
ersed by  minute  and  close-set  transverse  strias  over 
the  whole  or  a  part  of  the  fiber ;  and  he  conjectures 
that  if  the  enamel-fiber  be  a  mass  of  the  calcareous 
salts,  surrounded  by  an  organic  capsule,  that  the  stri.^ 
may  then  belong  to  the  capsule,  aod  not  to  the  enamel- 
fiber.  The  later  researches  of  Dr.  Schwann  add  to  the 
^probability  of  this  conjecture ;  and  the  absence  of  the 
minute  strise  in  the  enamel  of  fossil  mammalian  teeth, 
at  least  in  the  examples  which  I  have  submitted  to 
microscopic  investigation,  may  depend  upon  the  de- 
struction of  the  original  organic  constituent  of  the 
enamel. 

'^The  enamel-fibers  are  directed  at  nearly  right 
angles  to  the  surface  of  the  dentine,  and  their  central 
or  inner  extremities  rest  in  slight  but  regular  depres- 
sions on  the  periphery  of  the  coronal  dentine.  Thus 
in  the  hnman  tooth,  the  fibers  which  constitute  the 
masticating  surface  are  perpendicular,  or  nearly  so,  to 
that  surface,  while  those  at  the  lower  part  of  the  crown 
are  transverse,  and  consequently  have  a  position  best 
adapted  for  resisting  the  pressure  of  the  contiguous 
teeth,  and  for  meeting  the  direction  in  which  external 
forces  are  most  likely  to  impinge  upon  the  exposed 
crown  of  the  tooth.  The  strength  of  the  enamel-fibers 
is  further  increased  by  the  graceful,  wavy  curves  in 
which  they  are  disposed.  These  curves  are  in  some 
places  parallel,  in  others  opposed.  Their  concavities 
are  commonly  turned  toward  each  other,  where  the 
shorter  fibers,  which  do  not  reach  the  exterior  of  the 
enamel,  abut  l)y  their  gradually  attenuated  peripheral 
extremities  upon  the  longer  fibers.  Other  shorter  fibers 
extend  from  the  out3r  surface  of  the  enamel  toward 


EXAMEL    LIXES    PAEALLEL    AXD    WAVY.  XXI 

the  dentine,  and  are  wedged  into  the  interspaces  of 
the  longer  fibers.  In  the  teeth  of  fishes,  the  calciger- 
ous  tubes  or  fibers  of  the  enamel,  which  ramify  and 
subdivide  Hke  those  of  the  dentine,  have  their  trunks 
turned  in  the  opposite  direction,  or  toward  the  periph- 
ery of  the  tooth.  So  likewise  in  human  teeth  the 
analogous  condition  may  be  discerned  in  the  slightly 
augmented  diameter  of  the  enamel-fibers  at  their  pe- 
ripheral as  compared  with  their  central  extremii^ies. 
When  the  extremities  of  tlie  human  enamel-fibers  are 
examined  with  a  mignifying  power  of  300  linear 
dimensions,  by  reflected  light,  they  are  seen  to  be  co- 
adapted,  like  the  cells  of  a  honey-comb,  and,  like  these, 
to  be,  for  the  most  part,  hexagonal. 

"The  internal  surface  of  the  enamel  is  marked  by 
fine  transverse  lines  or  ridges,  of  which  Retzius  counted 
twenty-four  in  t'le  vertical  extent  of  one-tenth  of  an 
English  inch  of  the  crown  of  a  human  incisor.  These 
lines  are  parallel  and  wavy,  and,  like  the  analogous 
markings  on  the  surface  of  shells,  indicate  the  succes- 
sive formation  of  the  belts  of  enamel-fibers  that  encircle 
the  crown  of  the  tooth.  They  may  be  traced  around 
the  whole  crown,  but  are  very  faint  upon  its  inner  or 
posterior  surface.  Retzius  cites  Leeuwenhoek  as  the 
discoverer  of  these  superficial  transverse  lines  of  the 
enamel,  but  the  older  observer  supposed  them  to  be 
indicative  of  the  intervals  between  the  successive  move- 
ments in  the  cutting  of  the  tooth  through  the  gum. 

"  The  enamel,  by  virtue  of  its  physical  qualities  of 
density  and  durability,  forms  the  chief  mechanical 
defense  of  the  tooth,  and  is  consequently  limited  in 
most  simple  teeth  to  the  exterior  surface  of  the  exposed 
portion  of  the  dentine,  forming  the  crown  of  the  tooth. 
*      *      *      In  the  herbivorous  mammalia,  with  the 


XXll  INTRODUCTION. 

exceptiou  of  the  Edentata,  vertical  folds  or  processes 
of  the  enamel  are  continued  into  the  substance  of  the 
tooth,  varying  in  number,  form,  extent,  and  direction, 
and  producing,  by  their  superior  density  and  resistance, 
the  ridged  inequalities  of  the  grinding  surface  on  which 
its  efficacy  in  the  trituration  of  vegetable  substances 
depends." 

Dr.  Boon  Hayes's  thoughts  are  thus  recorded  in  a 
"Medical  Circular,"  extracts  from  which  appear  in 
"The  Veterinarian"  for  1853  (pp.  535-6): 

"In  the  first  place,  observe  the  pulpal  cavity,  which 
is  to  the  tooth  what  the  medullary  cavity  is  to  bone. 
Both  originate  in  the  same  way.  Into  it  passes  an 
artery,  a  vein,  and  a  nerve.  These  ramify  upon  the 
pulpal  surface,  the  artery  carrying  blood  to  the  denti- 
nal tubuli,  whence  the  liquor  sanguinis  (not  blood 
corpuscles)  proceeds  to  the  nourishment  of  this  ap- 
parently inorganic  mass. 

"In  the  teeth  of  some  animals  this  cavity  seems  to 
send  off  diverticula  between  the  dentinal  tubuli,  as  if 
for  the  purpose  of  supplying  them  with  more  vascu- 
larity. The  dentinal  tubes  open  on  the  walls  of  the 
pulpal  cavity,  and  thence  radiate  to  the  enamel  supe- 
riorly and  the  crusta  petrosa  inferiorly.  I  think  it 
would  not  be  difficult  to  prove  that  caries  of  the  teeth 
more  frequently  proceeds  from  inflammation  begin- 
ning in  this  cavity  than  from  any  other  cause. 

"When  the  tubes  of  the  dentine  are  examined  with  a 
high  magnifying  power,  and  by  transmitted  light,  they 
appear  dark.  They  are  much  more  minute  in  diameter 
than  the  blood  globules;  hence  the  liquor  sanguinis 
alone  can  penetrate  them  for  their  nourishment;   so 


PRIMARY    A2s'D    SECOXDAPtY    CURVES.  XXli'l 

that  the  teeth  are  in  the  same  condition  as  bone  in  this 
respect. 

"The  dentinal  tubes,  as  before  said,  appear  dark; 
the  Hgliter  and  apparently  broader  masses  are  the  real 
substance  of  the  dentine.  In  this,  and  especially  near 
the  layer  closest  to  the  enamel,  dentinal  cells  are  some- 
times seen,  which  may  probably  be  analogous  to  the 
lacunae  of  bone. 

"If  the  dentinal  curvatures  are  examined,  it  will  be 
seen  that  they  are  of  two  kinds.  One  set  is  in  bold 
and  evident  curves;  the  other  is  not  so  evident,  but  it 
exists,  nevertheless,  and  a  little  patience  and  a  high 
magnifying  power  will  demonstrate  the  fact  that  its 
curves  are  upon  the  curves  of  the  first  set.  The  former 
are  called  the  primary,  the  latter  the  secondary  curves 
of  the  dentinal  tubuli  (in  botanical  description,  a 
biserrated  leaf).  From  the  tubuli  minute  bracelets 
are  given  off  on  the  sides,  and  toward  the  end  the  tubes 
terminate,  either  in  cells,  by  anastomosis,  or  by  looping 
back  upon  themselves. 

"The  cement  at  first  envelops  the  whole  tooth,  but 
soon  wears  off  the  crown  and  as  far  down  as  the  neck. 
Compared  with  the  dentine  and  enamel,  it  is  very  soft, 
and  more  closely  resembles  bone ;  in  fact  in  some  ani- 
mals it  is  continuous  with  the  bone  of  the  jaw,  thus 
proving  its  identity.  It  contains  lacunas  and  canalic- 
uli,  and,  when  there  is  a  large  mass  of  it,  something 
like  Haversian  canals. 

"  There  is  a  great  analogy  between  tooth  and  bone. 
In  the  cement  there  is  absolute  likeness,  and  in  the 
dentine  analogies  too  striking  to  be  overlooked,  viz., 
the  tubuli,  analogous  to  the  canaliculi,  the  intertubular 
cells,  analogous  to  the  lacunae,  and  the  intertubular 
substance,  analogous  to  the  laminae  of  bone.     In  the 


XXIV  INTRODUCTION. 

enamel  the  greatest  departure  is  observable,  but  not 
wider  than  its  peculiar  function  suggests;  and  it  must 
be  remembered,  first,  that  it  is  the  least  constant  tissue 
of  the  teeth;  secondly,  that  its  chemical  composition 
is  very  much  the  same  as  that  of  the  dentine  and 
cement,  both  of  which  resemble  bone.  Lastly,  the 
analogy  is  completed  in  a  review  of  the  mode  of  tooth 
development.  Thus,  upon  a  mucous  papilla  a  largo 
quantity  of  gelatinous  matter  is  observable,  in  wliich 
certain  cells  appear.  The  gelatinous  matter  resembles 
the  incipient  cartilage  in  which  ossification  begins. 
This  papilla  is  supplied  with  an  artery,  which  nour- 
ishes its  cells,,  and  the  cells  gradually  so  develop  that 
the  older  ones  are  pushed  outward  and  form  the 
dentine." 

HOW   MADDER   AFFECTS   THE   TEETH. 

John  Hunter,  one  of  the  most  celebrated  physiolo- 
gists of  the  eighteenth  century,  made  many  experi- 
ments on  the  teeth  of  different  animals,  one  object 
being  to  determine  whether  they  were  vascular  or  not. 
His  conclusion  was  that  they  were  not  vascular,  and 
he  founded  his  belief  partly  upon  the  following  experi- 
ment ("  The  Human  Teeth,"  pp.  23-4) : 

"  Take,  for  example,  any  young  animal,  as  a  pig,  and 
feed  it  with  madder  for  three  or  four  weeks;  then  kill 
it.  On  examination  you  will  find  the  following  ap- 
pearances: First,  if  the  animal  had  some  parts  of  its 
teeth  formed  before  the  feeding  with  madder,  they 
will  be  known  by  their  remaining  of  the  natural  color; 
but  such  parts  of  the  teeth  as  were  formed  while  the 
animal  was  taking  the  madder  will  be  of  a  red  color. 
This  shows  that  it  is  only  those  parts  that  were  formed 
while  the  animal  wa.>  taking:  the  madder  that  are  dyed ; 


EED,    WHITE,    GOLDEIv    AXD  SILVER   HUES.      XXV 

for  what  were  already  formed  will  not  be  in  tlie  least 
tinged.  Tiiis  is  diiferent  in  all  other  bones;  for  we 
know  that  any  part  of  a  bone  which  is  already  formed 
is  capable  of  being  dyed  with  madder,  though  not  so 
fast  as  the  part  that  is  forming.  Therefore,  as  we  know 
that  all  other  bones  are  vascular,  and  are  thence  sus- 
ceptible of  the  dye,  we  may  readily  suppose  tiiat  the 
teeth  are  not  susceptible  of  it  after  being  once  formed. 
But  we  shall  carry  this  a  step  further:  If  you  feed  a 
pig  with  madder  for  some  time,  and  then  leave  it  off 
for  a  time  before  killing  it,  you  vvill  find  the  appear- 
ances as  above",  Avith  tliis  addition,  that  all  the  parts  of 
the  teeth  wliich  w^ere  formed  after  leaving  off  feeding 
w^ith  the  madder  will  be  white.  Here,  then,  in  some 
teeth  we  shall  have  white,  then  red,  and  then  white 
again;  and  so  we  shall  have  the  red  and  white  colors 
alternately  through  the  whole  tooth.* 

"This  experiment  shows  tliat  a  tooth,  once  tinged, 
does  not  lose  its  color.    Now,  as  all  other  bones  that 

*In  the  conchiding-  part  of  Moore's  "  Lalla  Rookli "  ("The 
Light  of  the  Harem"),  the  Enchantress  says  of  an  herb  with  the 
unmusical  name  of  "  Haschischat  ed  dab:" 

"  The  visions,  that  oft  to  worldly  eyes 
The  glitter  of  mines  unfold, 
Inhabit  the  mountain-herb,  that  dyes 
The  tooth  of  the  fawn  like  gold." 

A  reference  note  to  the  above  is  as  follows  :  "  An  herb  on 
Mount  Libauus,  which  is  said  to  communicate  a  yellow  golden 
hue  to  the  teeth  of  the  goats  and  other  animals  that  graze  upon 
it.  Nisbuhr  thinks  this  may  be  the  herb  which  the  Eastern 
alchemists  look  to  as  a  means  of  making  gold.  '  Most  of  those 
alchemical  enthusiasts  thiuk  themselves  sure  of  success  if  they 
could  but  find  out  the  herb  which  gilds  the  teeth  and  gives  a  yel- 
low color  to  the  flesh  of  the  she-p  that  eat  it.  Even  the  oil  of  this 
plant  must  be  of  a  golden  color.  It  is  called  Hasduschat  ed  dab.' 
Father  Jerome  Dandini,  however,  asserts  that  the  teeth  of  the 


XXVI  INTRODUCTION^. 

have  been  tinged  lose  their  color  in  time,  when  the 
animal  leaves  off  feeding  with  the  madder  (though 
very  slowly),  and  as  that  dye  must  be  taken  into  the 
constitution  by  the  absorbents,  it  seems  that  the  teeth 
are  without  absorbents  as  well  as  other  vessels." 

The  editor  of  Hunter's  "Treatise,"  Thomas  Bell, 
F.R.S.,  differed  with  Hunter  about  the  vascularity  of 
the  teeth.  He  thus  concludes  a  note  on  the  above 
quotation : 

■"  The  truth  appears  to  be  that  the  teeth  are  organ- 
ized bodies,  having  nerves  and  absorbent  and  circula- 
ting vessels,  but  possessing  a  low  degree  of  living 
power,  and  so  dense  a  structure  as  to  exhibit  phenom- 
ena, both  in  their  healthy  and  diseased  condition, 
which  are  very  dissimilar  from  those  which  are  ob- 
served in  true  osseous  structures." 

TEANSPLAKTING   TEETH. 

The  transplanting  of  teeth,  which  Dr.  Hunter  says 
is  "  similar  to  the  ingrafting  of  trees,"  is  expatiated 
upon  at  some  length.  He  then  gives  an  account  of  a 
case  of  transplanting  which  he  admits  "is  not  gener- 
ally attended  with  success,"  he  having  "succeeded  but 
once  out  of  a  great  number  of  trials."  It  is  as  follows 
(«  The  Human  Teeth,"  pp.  100-101) : 

"  I  took  a  sound  tooth  from  a  person's  head ;  then 

goats  at  Mount  Libanns  are  of  a  silver  color,  and  adds :  '  This 
confirms  to  me  that  which  I  observed  in  Candia,  to  wit,  that 
the  animals  that  live  on  Mount  Ida  eat  a  certain  herb  which 
renders  their  teeth  of  a  golden  color,  which,  according  to  my 
judgment  cannot  otherwise  y)roceed  than  from  the  mines  which 
are  under  ground.' — Dandini,  Voyage  to  Mount  Libanns" 


Gr.AFIIXG    GEr.MS    OF   DCGS'   TEETIT.  XXvii 

made  a  wound  in  a  cock's  comb,  pressed  the  root  into 
it,  and  fiistened  it  with  threads.  The  cock  was  killed 
some  months  after,  and  I  injected  the  head  with  a  very 
minute  injection.  I  then  put  the  comb  into  a  weak 
acid.  The  tooth  was  softened,  and  I  divided  it  lono-i- 
tudinally.  Its  vessels  were  well  injected,  the  external 
surface  adhering  to  the  comb  by  vessels  similar  to  the 
union  of  a  tooth  with  the  gum  and  sockets."* 

*  MM.  E.  Magitot,  C.  Legros,  and  C.  Robin  have  experimented 
in  trans[.lanting  tlie  follicles  or  germs  of  dogs'  teev;h,  an  account 
of  wliicli  appears  in  "  Comptes  Rendus"  for  1874.     They  say  : 

"Oar  experiments  comprised  88  grafts,  mostly  from  newly-born 
dogs,  but  some  were  23  and  even  58  days  old.  The  animals 
were  invariably  sacrificed  by  the  pricking  of  the  bulbs,  and 
the  jaws  were  opened  at  once,  to  lay  the  follicles  bare.  One-half 
of  both  jaws  thus  served  to  supply  the  grafts,  while  the  other 
was  kept  for  a  standard  of  comparison.  The  dog's  on  which  the 
grafts  were  applied  were  usually  adults,  but  sometimes  of  the 
same  age  and  bearing  as  those  that  supphed  them.  The  germs 
were  rapidly  isolated  from  the  dental  gutters,  and  introduced  at 
once.  In  some  instances  they  were  dipped  for  a  few  minutes  in 
the  blood's  serum  of  the  sacrificed  animal,  which  was  kept  by 
the  bath  (bain-marie)  at  a  temperature  of  from  30^  to  35°  C. 
They  were  introduced  under  the  skin  of  the  nap.?  of  the  neck, 
the  top  of  the  head,  and  the  dorsal  and  lumbar  regions.  In  36 
cases  the  process  of  application  consisted  of  a  simjde  incision  and 
the  introduction  of  the  graft  2  or  3  centimeters  from  the  open- 
ing, which  was  closed  by  two  sutural  stitches.  In  the  other  53 
cases  a  special  trocar  of  an  interior  diameter  of  7  millimeters  was 
used,  which  allowed  a  swifter  and  surer  transplantation,  but  it 
did  not  appear  to  exert  an  appreciable  influence  on  the  results. 

"  Ten  grafts  were  made  from  newly- born  dogs  on  adult  guinea- 
pigs,  divided  as  follows :  Whole  follicles,  6 ;  isolated  enamel- 
organs,  3  ;  bulb  alone,  1.  The  results  were  all  negative— caused 
by  resorption  and  suppuration— corroborating  M.  Bert's  experi- 
ences in  grafts  between  animals  of  different  zoological  orders. 

"  The  78  other  grafts  were  made  on  newly-born,  young,  and 
adult  dogs,  and  were  maintained  from  13  to  54  days.  The  35 
grafts  that  remained  54  days  resorbed  themselves.  The  experi- 
ments in  detail  were  as  follows :  1.  Isolated  whole  follicles,  26. 
2.  Follicles  with  a  portion  of  the  maxillary  bone,  5.     3.  Isolated 


XXVm  IXTRODUCTIOI!?'. 

This  appears  to  prove  that  Dr.  Hunter  was  right 
whcD  he  said  that  teeth  "are  capable  of  uniting  with 

bulbs,  16.  4.  Bulbs  witli  a  cap  of  rudimentary  dentine,  7.  5. 
Isolated  caps  of  dentine,  4.  6.  Isolated  enamel -organs,  with  a 
slired  of  buccal  raucous  membrane,  19.  7.  Enamel  organs,  with 
a  cap  of  dentine  adhering,  1.  The  results  were :  Of  the  first,  7 
kept  alive  and  grew  steadily,  except  in  one  instance,  in  which  a 
disturbed  nutrition  brought  on  the  formation  of  globulary  den- 
tine and  irregular  stacks  of  enamel  prisms.  The  second  gave  3 
suppurations  and  2  resorptions,  again  corroborating  Mons.  Bert's 
ex  )eriments.  The  third  gave  3  positive  results,  in  two  of  which 
a  nsv/  cap  of  dentine  was  ])roduced.  quite  regular,  but  globulous 
and  somewhat  altered  in  its  nutrition.  The  other  was  without 
enamel.  In  the  fourth  experiment  tlie  bulbs  could  not  be  found ; 
they  underwent  resorption.  When  conijiared  with  the  preced- 
ing experiment,  this  result  is  astonishing;  but  it  should  be  un- 
derstood that  these  grafts  were  maintained  from  43  to  51  dnys. 
Of  the  fifth  a  single  one  kept  alive,  but  without  showing  any 
growth.  It  remained  stationary  48  days.  The  sixth  invariably 
ended  in  resorption,  notwithstanding  we  were  careful  to  graft 
the  shred  of  mucous  membrane,  which  supplies  the  organ  with 
nutritive  vessels.  This  result  is  not  surprising  when  the  exces- 
sive frailty  of  this  tissue  and  its  lack  of  vascularity  are  consid- 
ered. Some  of  the  negative  grafts  were  either  reduced  in  size, 
being  evidently  in  process  of  resorption,  or  underwent  the  oily 
transformation.  Others  caused  abscesses,  and  were  eliminated. 
"  Conc'usioas. — 1.  The  grafts  gave  favorable  results  only  be- 
tween animals  of  the  same  zoological  order.  2.  The  isolated 
whole  follicles  and  bulbs  may  live  and  develop  themselves.  3. 
The  transplanting  of  more  or  less  voluminous  portions  of  jaws 
with  the  follicles  failed  through  suppuration  or  resorption.  4. 
The  grafts  of  the  enamel  organ,  isolated,  seem  invariably  given 
up  to  resorption.  5.  Under  certain  circumstances  the  g7'<)wth  is 
regular,  with,  no  other  difference  from  that  in  the  normal  state 
than  a  notice  ible  slowness  in  the  phenomena  of  evolution.  6. 
Under  other  circumstances  there  is  trouble  in  the  formation  of 
the  dentine  and  enamel,  the  study  of  which,  however,  may  be  ap- 
plied to  the  elucidation  of  the  phenomena,  still  so  dark,  of  tooth 
development.  7.  The  experiments  are  an  acquisition  to  the  lit- 
erature of  and  may  be  compared  with  other  surgical  grafts."* 

■■'  For  the  Iranplation  of  the  above  interestine:  article  (from  the  Reports  of 
the  French  Academy)  I  am  indebted  to  Monsieur  C.  Raoux.  of  New  York. 


THE   TEETH    LIVI:N"G    ORGANISMS.  XXIX 

any  part  of  a  living  body."    Mr.  Bell  tlius  concludes 
a  note  on  tlie  above  case  of  transplanting: 

"  The  experiment  lias  an  interest  attached  to  it  far 
more  important  than  its  having  given  rise  to  the  tem- 
porary adoption  of  an  objectionable  operation.  In  the 
result  of  this  experiment  may  be  found  an  interesting 
collateral  argument  in  favor  of  the  organized  structure 
of  the  teeth,  and  their  actual  living  connection  with 
the  body.  The  vessels  of  the  tooth,  we  are  told,  were 
well  injected,  and  the  external  surface  adhered  everj^- 
where  to  the  comb  by  vessels.  To  what  purpose  are 
these  vessels  formed,  what  object  can  be  possibly  ful- 
filled by  the  existence  of  a  vascular  pulp  in  the  internal 
cavity,  and  a  vascular  periosteum  covering  the  external 
surface — so  obviously  vascular  that  it  was  -well  injected 
from  the  vessels  of  a  cock's  comb,  into  which  it  had 
been  transplanted — unless  they  are  intended  to  nourish 
the  bony  substance  of  which  the  tooth  consists,  and  to 
form  the  medium  of  its  connection  with  the  general 
system  ?'' 

Prof.  Richard  Owen  says  ("  Odontography,"  vol.  i, 
p.  470) : 

"  The  saving  of  material  is  the  least  of  the  benefits 
gained  by  this  tubular  structure  of  the  dentine.  The 
vitality  of  the  tissue,  which  Hunter  recognized  so 
forcibly,  but  which,  being  equally  convinced  of  the 
noil- vascularity  of  the  tissue,  he  was  unable  to  explain 
— *  willing  rather  to  enunciate  an  apparent  paradox  or 
be  taunted  with  dilemma,  than  yield  one  iota  of  either 
of  his  convictions'* — is  explicable  by  the  possible  and 

*Prof.  Owen  quotes  from  Bell's  "  notes"  in  Hunter's  "Humau 
Teeth." 


XXX  INTRODUCTION-. 

highly  probable  fact  of  a  circulation  of  the  colorless 
plasma  of  the  blood  through  the  dentinal  tubes.  That 
some  elementary  prolongations  of  nerve  may  also  be 
continued  into  these  tubes,  who  can  confidently  deny  ?" 

As  Prof.  Owen  says  the  "  teeth  are  always  most 
intimately  related  to  the  food  and  habits  of  the  ani- 
mal," it  would  be  interesting  and  perhaps  useful  to 
ascertain  what  effect  sugar  and  other  unnsual  articles 
of  diet  would  have  on  horses'  teeth.  In  the  interest 
of  science,  experiments  appear  to  be  in  order.  In  this 
connection  the  following  paragraph,  a  part  of  which 
may  be  found  in  Prof  WiUiam  Youatt's  work,  "The 
Horse  "  (p.  135),  the  remainder  in  '^  The  Veterinarian/' 
is  interesting: 

"  Surgeon  Black,  of  the  Fourteenth  Dragoons,  says 
that  sugar  was  tried  as  an  article  of  food  during  the 
Peninsular  War.  Ten  horses  were  selected,  each  of 
which  got  eight  pounds  a  day.  They  took  it  very 
readily,  and  their  coats  became  fine,  smooth,  and 
glossy.  They  got  no  corn,  and  only  seven  pounds  of 
hay  instead  of  twelve,  the  ordinary  allowance.  The 
sugar  supplied  the  place  of  corn  so  well,  that  it  would 
probably  have  been  given  abroad  ;  but  peace  came,  and 
with  it  corn.  The  horses  returned  to  their  usual  diet, 
but  several  of  them  became  crib-biters.  The  experi- 
ment was  made  at  the  Brighton  depot,  during  a  period 
of  three  months.  To  prevent  the  sugar  from  being 
used  for  other  purposes,  it  was  scented  with  assafetida, 
but  the  latter  did  not  produce  any  apparent  effect  on 
the  horses." 


HORSES'    TEETH. 


CHAPTER    I. 

TOOTH-GERMS    (0D0NT0GEN"Y). 

Periods  at  wliicli  the  Germs  are  visible  in  the  Fetus. — DeDtine 
and  Enamel  Germs. — A  Cement  Germ  in  the  Foal. — The 
Horse's  Upper  Grinders  said  to  be  develoi-ed  from  Five 
Germs,  the  Lower  from  Four, —  Similar  development  of  the 
Human  Teeth.— Monsieur  Magitot's  Researches. 

FuRKOWS  ill  what  is  subsequently  transformed  into 
jawbones,  in  wliich  tooth-germs  are,  as  it  were,  planted, 
are  Nature's  first  visible  preparation  for  the  develop- 
ment of  the  teeth.  According  to  Prof.  William  You- 
att,  the  germs  of  the  temporary  teeth  are  visible  seven 
or  eight  months  before  the  foal  is  born.  Three  months 
before  its  birth  the  germs  of  the  permanent  teeth  are 
also  visible,  a  distinct  partition  separating  them  from 
the  temporary.  At  this  time,  according  to  Veterinary 
Dentist  C.  D.  House,  the  capsules  or  bags  (also  called 
follicles,  sacs,  &c.),  containing  the  tooth-pulps*'  of  the 

*  The  pulp  in  the  cavity  of  a  fall-grown  tooth  is  a  delicate 
mass  of  connective  tissue,  containiog  both  blood-vessels  and 
nerves.  Its  external  layer  consists  of  large  nucleated  cells,  the 
odontoblasts,  provided  with  long  branching  processes  which  line 
the  dental  canals.  Boll  thinks  the  nerves'  delicate  terminal 
fibrils  accompany  the  processes  into  the  canals. —  Woodicard. 

For  development  of  elephant  tooth-germs  see  Appendix. 


3^  TOOTH-GERMS. 

future  temporary  teeth  are  about  the  size  of  small  peas. 
They  will  bear  some  pressure  between  the  fingers,  the 
indentions  springing  back  like  those  of  an  India  rub- 
ber ball. 

Tiie  nature  of  tooth-germs  and  the  development  of 
teeth  have  been  studied  with  some  diligence  by  scien- 
tific men — Dr.  John  Hunter,  it  is  said,  making  the  first 
important  discoveries  in  connection  with  the  science. 
The  discussion  of  tliis  interesting  and,  to  students, 
useful  subject  is  left  to  these  men.  There  is  some 
conflict  in  their  vicAVS,  but  it  should  be  remembered 
that  the  extracts  reflect  the  opinions  of  men  from 
Hunter's  time  (over  a  century  ago),  to  1876.  The  de- 
velopment of  tooth-germs  being  the  same  in  principle 
(though  different  in  detail)  in  all  mammals,  the  matter 
which  follows  (as  has  been  said  of  that  in  the  ^-Intro- 
duction"), is  as  applicable  to  the  horse  as  to  man. 

In  the  Introduction  to  his  "Odontography"  (Lon- 
don, 1844),  Prof.  Richard  Owen  says: 

"In  the  development  of  a  tooth  a  matrix  of  equal 
complexity  was  first  recognized  to  be  concerned  by 
John  Hunter,  the  several  parts  of  this  matrix  being 
first  distinctly  indicated  in  the  ^Natural  History  of 
the  Human  Teeth.'  *  *  *  Hunter  has  been  gen- 
erally regarded  by  phj'siologists  as  being  the  author,  of 
the  theory  that  the  pulp  stood  to  the  tooth-bone  in  the 
relation  of  a  gland  to  its  secretion  ;  that  the  formative 
virtue  of  the  pulp  resided  in  its  surface  ;  that  the  den- 
tine was  deposited  upon  and  by  the  formative  or  secre- 
tive surface  in  successive  layers,  and  that  the  pulp, 
exhausted,  as  it  were,  by  its  secretive  activit}-,  dimin- 
ished in  size  as  the  formation  of  the  tooth  proceeded, 
except  in  certain  species,  in  which  it  was  persistent. 


and  maintained  an  equable  secretion  of  the  dentine 
throughout  the  lifetime  of  the  auimal.  This  idea  of 
the  pulp's  function  has  predominated  in  the  minds  of 
most  subsequent  writers  on  the  development  of  the 
tectii.  *  ^  ''  * 

"  Three  formative  organs  are  developed  for  the  three 
principal  or  normal  dental  tissues,  the  '  dentinal-pulp/ 
or  pulp  proper,  for  the  dentine,  the  'capsule'  for  the 
cement,  and  the  ^enamel-pulp'  for  the  enamel.  The 
essential  fundamental  structure  of  each  formative 
organ  is  cellular,  but  the  cells  differ  m  each  organ, 
and  derive  their  specific  characters  from  the  properties 
and  metamorphoses  of  their  nucleus,  upon  which  the 
specific  microscopical  characters  of  the  resulting  calci- 
fied substances  depend. 

"In  the  cells  of  the  dentinal-pulp  the  nucleus  fills 
the  parent  cell  with  a  progeny  of  nucleoli  before  the 
w^ork  of  calcification  begins.  In  the  enamel-pulp  the 
nucleus  of  the  cell  disappears,  like  the  cytoblast  of  the 
embryo  plant  m  the  formation  of  most  vegetable  tis- 
sues. In  the  cells  of  the  capsule  the  nucleus  neither 
perishes  nor  propagates,  but  retains  its  individuahty, 
and  o-ives  oricrin  to  the  mos^  characteristic  feature  of 
the  cement,  viz.,  the  radiated  cells. 

"The  primordial  material  of  each  constituent  of  the 
tooth-matrix  is  derived  from  the  blood,  and  special 
a,rraugements  of  the  blood-vessels  preexist  to  the  devel- 
opment and  growth  of  the  constituent  substances.  A 
pencil  of  capillaries  is  directed  to  a  particular  spot  in 
the  primitive  dentiparous  groove,  and  terminates  there 
by  a  looped  network,  from  which  spot  a  group  of  nu- 
cleated cells  begins  to  arise  in  the  form  of  a  papilla. 


-ft-' 


"The  primary  dentinal  papilla  and  its  capsule  rap- 


34  TOOTH-aEHMS. 

idly  increase  by  successive  additious  of  nucleated  cells^ 
apparently  derived  from  material  supplied  by  the  cap- 
illary plexus  at  the  base.  The  capillaries  now  begin 
to  penetrate  the  substance  of  the  pulp  itself,  where 
they  present  a  subparallel  or  slightly  diverging  pencil- 
late  arrangerhent,  but  preserve  their  looped  and  retic- 
ulate termination  near  the  apex  of  the  pulp.  Fine 
branches  of  nerves  accompany  the  capillaries,  and  ter- 
minate also  in  loops.  *  *  *  The  primary  cells  and 
the  capillary  vessels  and  nerves  are  imbedded  in  and 
supported  by  a  homogeneous,  minutely  subgranular, 
mucilaginous  substance,  the  4)lastema.'  *  *  *  ^he 
vascularity  of  the  dentinal-pulp,  and  especially  the 
rich  network  of  looped  capillaries  that  adorns  the 
formative  peripheral  layer  at  the  period  of  its  func- 
tional activity,  have  attracted  general  notice,  and  have 
been  described  by  Hunter  and  subsequent  authors.  By 
most  this  phenomenon  has  been  regarded  as  evidence 
of  the  secreting  function  of  the  surface  of  the  pulp, 
and  the  dentine  as  an  outpouring  from  that  vascular 
surface  which  w^as  supposed  to  shrink  or  withdraw 
from  the  matter  excreted.  *  *  ^ 

"The  enamel-pulp  differs  from  the  dentinal-pulp  at 
its  first  formation  by  the  more  fluid  state  of  its  blas- 
tema, and  by  the  fewer  and  more  minute  cells  which 
it  contains.  The  source  of  this  fluid  blastema  appears 
to  be  the  free  inner  vascular  surface  of  the  capsule. 
As  it  approaches  the  dentinal-pulp  the  blastema  ac- 
quires more  consistence  by  an  increased  number  of  its 
granules,  and  it  contains  more  numerous  and  larger 
cells.  Many  of  these  show  a  nuclear  spot,  others  a 
nucleus  and  nucleolus.  The  spherical  nucleolar  cells 
in  the  part  of  the  blastema  further  from  the  capsule 
are  so  numerous  as  to  form  an  aggregate  mass,  with  a 


DEFIXIXG  THE  BLASTEMA.  35 

small  quantity  of  tho  condensed  blastema  in  the 
minute  interspaces  left  between  the  cells,  which  are 
pressed  together  into  hexagonal  or  polygonal  forms. 
*  ♦  *  rp|-,Q  ^^ij^  q£  ^i-^Q  f^y^^i  metamorphosis  of  the 
cells  into  the  molds  for  the  reception  of  the  solidifying 
salts  IS  confined  to  close  contiguity  with  the  surface  of 
the  dentinal-pulp.  Here  the  cells  increase  in  length, 
lose  all  trace  of  their  nucleus,  and  become  converted 
into  long  and  slender  cylinders,  usually  pointed  at  both 
ends,  and  pressed  by  mutual  contact  into  a  prismatic 
form.  These  cylinders  have  the  property  of  imbibing 
the  calcareous  salts  of  the  enamel  from  the  plasmatic 
fluid,  and  of  compacting  them  in  a  clear  and  almost 
crystalline  state  m  their  interior.         *         *  * 

"The  blastema  or  fundamental  tissue  of  the  capsule 
is,  at  first,  semitransparent  and  of  a  pearly  or  opaline 
color,  but  IS  soon  richly  ornamented  by  the  plexiform 
distribution  of  the  blood-vessels.  As  the  period  of  its 
calcification  approaches,  which  is  later  than  that  of 
the  dentinal-pulp,  it  becomes  denser,  and  exhibits  nu- 
merous nucleated  cells.  The  blastema  itself  presents 
more  evidently  a  fine  cellular  or  granular  structure,  in 
which  the  calcareous  salts  are  impacted  in  a  compara- 
tively clear  state,  constituting  the  framework  of  the 
cemental  tissue.  The  characteristic  features  of  this 
tissue  are  due  to  the  action  of  the  proper  nucleated 
cells  upon  the  salts  of  the  plasma  diffused  through  the 
blastema  m  which  those  cells  are  imbedded,  the  cells 
being  characterized  by  a  single,  large,  granular  nu- 
cleus, which  almost  fills  the  clear  area  of  the  cell  itself 
If,  when' the  formation  of  the  cement  has  begiin  m  the 
incisor  or  molar  of  a  colt,  one  of  the  detached  specks 
of  that  substance,  witli  the  surrounding  and  adhering 
part  of  the  inner  surface  of  the  capsule  in  which  it  is 


36  TOOTH-GERMS. 

imbedded,  be  exaDiined,  the  nucleated  cells  are  seen, 
closely  aggregated  around  the  calcified  part,  in  con- 
centric rows,  the  cells  of  which  are  further  apart  as 
the  rows  recede  from  the  field  of  calcification.  Those 
next  the  cement  rest  in  cup-shaped  cavities  in  the 
periphery  of  the  calcified  part,  just  as  the  first  calcified 
cells  of  the  thick  cement  which  covers  the  crown  of  a 
complex  molar  are  lodged  in  cavities  on  the  exterior  of 
the  enamel.  These  exterior  cavities  of  the  cement  are 
formed  by  centrifugal  extension  of  the  calcifying  pro- 
cess in  the  blastema  m  which  the  cells  are  imbedded. 
The  calcareous  salts  penetrate  in  a  clearer  and  more 
compact  state  the  cavity  of  the  cell,  but  their  progress 
is  arrested  apparently  by  the  nucleus,  which  maintains 
an  irregular  area,  partly  occupied  by  the  salts  in  a  sub- 
granular,  opake  condition,  but  chiefly  concerned  in 
the  reception  and  transit  of  the  plasmatic  fluid,  which 
enters  and  escapes  by  the  minute  tubes  that  are  sub- 
sequently developed  from  the  nucleolar  cavity  as  calci- 
fication proceeds. 

^'  The  radiated  cells  or  cavities  thus  formed  are  the 
most  common  characteristic  of  the  cement,  but  not  the 
constant  one.  The  layer  of  the  capsule  which  sur- 
rounds the  crowm  of  the  human  teetli  and  of  the 
simple  teeth  of  quadrumana  and  carnivora,  consists 
simply  of  the  granular  blastema,  without  nucleated 
cell?,  and  the  radiated  corpuscles  are,  consequently,  liot 
developed  m  the  cement  which  results  from  its  calci- 
fication. In  the  thicker  part  of  the  inflected  folds  of 
the  capsule  of  the  complex  teeth  of  the  herbivora, 
traces  of  the  vascularity  of  that  part  of  the  matrix  are 
persistent,  the  blastema  calcifying  around  certain  of 
the  capillaries,  and  forming  the  medullary  canals. 
The  varieties  of  these  canals  are  traversed  bv  minute 


PROF.   TOMES^S  THEORY.  37 

tnbnles,  continued  from  or  commnnicating  with  the 
radiated  cells.  These  tubules,  and  the  more  parallel 
ones  which  traverse  the  thickness  of  the  cement  in 
many  mammalia,  are  the  remains  of  linear  series  of 
the  minute  granules  of  the  blastema-.       *        *       * 

"  The  general  form  of  the  dent<il  matrix  and  its  rela- 
tion with  its  calciiied  product,  boar  a  close  analogy 
with  those  of  the  formative  organ  of  hairs,  bristles,  and 
other  productions  of  the  epideiTnal  system.  In  these 
the  papilla,  or  pulp,  is  developed  from  the  external 
skin;  in  the  teeth,  from  the  mucous  membrane,  or 
internal  skin."  *  *  *  * 

Prof.  Charles  S.  Tomes^  among  dentists  a  recognized 
authority,  differs  with  Messrs.  Hunter  and  Owen  as 
to  the  pulp's  secretive  office,  claiming  that  a  tooth  is 
formed  by  a  partial  metamorphosis  of  its  pulp.  He 
says  ("Manual  of  Dental  Anatomy,  Human  and  Com- 
parative," pp.  104-5-6) : 

"  Prior  to  the  beginning  of  any  calcification,  there 
is  always  a  special  disposition  of  the  soft  tissues  at  the 
spot  where  a  tooth  is  destined  to  be  formed,  and  the 
name  of  'tooth-germ'  is  given  to  those  portions  of  the 
soft  tissue  which  are  thus  specially  arranged.  All,  or 
a  part  only,  of  the  soft  structures  making  up  a  tooth- 
germ  become  converted  into  the  dental  tissue  by  a 
deposition  of  salts  of  lime  within  their  own  substance, 
so  that  an  actual  conversion  of  at  least  some  portions 
of  the  germ  into  tooth  takes  place.  The  tooth  is  not 
secreted  or  excreted  by  the  germ,  but  an  actual  meta- 
morphosis of  the  latter  takes  place. 

"  The  principal  tissues,  namely,  dentine,  enamel,  and 
cement,  are  formed  from  different  parts  of  the  tooth- 
germ;  hence  we  are  accustomed  to  speak  of  the  enamel- 


38  TOOTH-QERMS. 

germ  and  the  deiitine-germ.  The  existence  of  a  spe- 
cial cement-germ  is  very  doubtful,  some  writers  assert- 
ing, others  denying  its  existence.         *  *  * 

''  Tooth-germs  are  never  formed  upon  the  surface, 
but  are  situated  a  httle  distance  beneath  it,  lying  in 
some  animals  at  a  considerable  depth.  Every  known 
tooth-germ  consists  in  the  tirst  instance  of  two  por- 
tions, and  two  only,  the  enamel  and  dentine  germs. 
These  are  derived  from  distinct  sources,  the  former 
being  a  special  development  from  the  epithelium  of 
the  mouth,  the  latter  from  the  more  deeply  lying  parts 
of  the  mucous  membrane.  Other  things,  such  as  a 
tooth-capsule,  may  be  subsequently  and  secondarily 
formed.  The  existence  of  an  enamel-organ  in  an  early 
stage  is  independent  of  any  subsequent  formation  of 
enamel  by  its  own  conversion  into  a  calcified  tissue,  for 
I  have  shown  it  to  be  found  in  the  germs  of  teeth 
whicli  have  no  enamel;  in  fact,  in  all  tooth-germs 
whatever. 

"That  part  of  the  tooth-germ  destined  to  become 
dentine  is  often  called  the  dentine  papilla,  having 
acquired  this  name  from  its  papilliform  shape;  and  in 
a  certain  sense  it  is  true  that  the  enamel-organ  is  the 
epithelium  of  the  dentine  papilla.  Yet,  although  not 
absolutely  untrue,  such  an  expression  might  mislead 
by  implying  that  the  enamel  organ  is  a  secondary  de- 
velopment, whereas  its  appearance  is  contemporaneous 
"with,  if  not  antecedent  to,  that  of  the  dentine-germ. 
The  most  general  account  that  I  am  able  to  give  of  the 
process  is,  that  the  deeper  layer  of  the  oral  epithelium 
sends  dow^i  into  the  subjacent  tissue  a  process,  the 
shape  and  structure  of  whicli  is,  in  most  animals,  dis- 
tinguishable and  characteristic  before  the  dentine- 
germ  has  taken  any  definite  form.     This  process  en- 


THE  ORAL  EPITHELIUM.  39 

larges  at  its  end,  and,  as  seen  in  section,  becomes 
divaricated,  so  that  it  bears  some  resemblance  to  an 
inverted  letter  Y ;  or  it  might  be  better  compared  to  a 
bell-jar  with  a  handle.  This  constitutes  the  early  stage 
of  an  enamel-germ,  while  beneath  it,  in  the  mucous 
tissue,  the  dentine-germ  assumes  its  papilliform  shape. 
Tiie  details  of  the  process  varying  in  different  animals, 
I  will  at  once  proceed  to  the  description  of  the  devel- 
opment of  teeth  in  the  various  groups." 

Prof.  Tomes's  views  of  the  development  of  tooth- 
germs  in  mammals  are  thus  summarized  by  himself 
("Philosoi)hical  Transactions  Royal  Society,"  1875, 
part  i,  p.  285) : 

"1.  There  is  never,  at  any  stage,  an  open  groove 
from  the  bottom  of  which  papilla?  rise  up. 

"2.  That  the  first  recognizable  change  in  the  region 
of  a  forming  tooth-germ  is  a  dipping  down  of  a  process 
of  the  oral  epithelium,  looking,  m  section  transverse 
to  the  jaw,  like  a  deep  simple  tubular  gland,  which 
descends  into  the  submucous  tissue,  and  ultimately 
forms  the  enamel-organ. 

"  3.  That  subsequently  to  the  descent  of  the  so-called 
enamel-germ,  the  changes  in  the  sul)jacent  tissue  re- 
sulting in  the  formation  of  the  dentine  papilla  take 
place  opposite  to  its  end,  and  not  at  its  surface. 

"4.  That  the  permanent  tooth -germs  first  appear  as 
offshoots  from  the  epithelial  process  concerned  in  the 
formation  of  the  deciduous  tooth-germ  (Kolliker),  the 
first  permanent  molar  being  derived  from  a  primary 
dipping  down  (like  a  deciduous  tooth),  the  second  de- 
riving its  enamel-germ  from  the  epithelial  neok  of  the 
first,  and  the  third  from  that  of  the  second  (Legros 
and  Magitot)/' 


40  TOOTH-GEEMS. 

Again,  in  the  Society's  TraRsactmis  for  1876  (p.  265), 
Prof.  Tomes  says: 

''1.  It  is  desirable  to  abandon  the  terms  ^papillary,' 
*  follicular,'  and  'eruptive'  stages,  inasmuch  as  they 
are  hypothetical  and  arbitrary,  and  correspond  to  no 
serial  conditions  verified  by  observation. 

''2.  In  all  animals  a  tooth-germ  consists  primarily 
of  two  structures,  and  only  two — the  dentine-germ 
and  the  enamel-germ*.  The  simplest  tooth-germ  never 
comprises  anything  more.  When  a  capsnle  is  devel- 
oped, it  is  derived  partly  from  a  secondary  upgrowth 
of  the  tissue  at  the  base  of  the  dentine  germ,  and  partly 
from  an  accidental  condensation  of  the  surrounding 
connective  tissue. 

"3.  The  existence  of  an  enamel-organ  is  quite  uni- 
versal, and  is  in  no  way  dependent  on  the  presence  or 
absence  of  enamel  on  the  completed  tooth,  although 
the  degree  to  which  it  is  developed  has  distinct  relation 
to  the  thickness  of  the  future  enamel. 

"4.  So  far  as  my  researches  go,  a  stellate  reticulum, 
constituting  a  large  bulk  of  the  enamel-organ,  is  a 
structure  confined  to  the  mammalia.  (It  is  absent  in 
the  armadillo,  and  I  should  infer  from  Mr.  Turner's 
description,  in  the  narwhal  also). 

"5.  x\s  laid  down  by  Profs.  Huxley  and  Kolliker, 
the  dentine-papilla  is  beyond  all  question  a  dermal 
structure,  the  enamel-organ  an  epithelial  or  epidermic 
structure.  As  I  believe  it  can  be  shown  that  the  enamel 
is  formed  by  an  actual  conversion  of  the  cells  of  the 
enamel-organ,  this  makes  the  dentine  a  dermal  and 
the  enamel  an  epidermic  structure. 

"6.  In  teleosts  the  new  enamel-germs  are  formed 
directly  from  tlie  oral  epithelium.  They  are  new  for- 
mations, and  arise  quite  independently  of  any  portion 


MONSIEUR  CHAUVEAU'S  THEORY.  41 

of  the  germs  of  the  teeth  which  preceded  them.  In 
mammals  and  reptiles,  and  in  some  of  the  batrachia, 
new  tooth-germs  are  developed  from  portions  of  tlieu* 
predecessors. 

''  7.  In  all  animals  examined  the  phenomena  are  yerj 
uniform.  A  process  dips  in  from  the  oral  epithelium, 
often  to  a  great  depth,  its  end  becoming  transformed 
into  an  enamel-organ  coineidentally  with  the  formation 
of  a  dentine-papilla  beneath  it.  The  differences  lie 
rather  in  snoh  minor  details  as  the  extent  to  which  a 
eapsnle  is  developed,  and  therefore  no  such  generali- 
zation as  that  the  teeth  of  fish  in  their  development 
represent  only  an  earlier  stage  of  the  development  of 
the  teeth  of  mammalia  can  be  drawn.^' 

Monsieur  A.  Chanvean's  theory  of  the  development 
of  tooth-germs  is  as  follows  ("  Comparative  Anatomy 
of  the  Domesticated  Animals,"  p.  921) : 

*'  The  teeth  are  developed  in  the  interior  of  a  cavity, 
named  the  dental  folUcla  or  sac,  by  means  of  the  ele- 
ments of  three  germs,  one  belonging  to  the  dentine, 
another  to  the  enamel,  and  a  third  to  the  cement.  The 
dental  follicle  is  an  oval  cavity,  with  walls  composed  of 
two  layers.  The  external  is  fibrous  and  complete;  the 
internal,  soft  and  gelatinons,  is  allied  at  the  bottom  to 
the  dentine-germ.  The  latter  is  a  prominence,  which 
is  detached  from  the  bottom  of  the  follicle,  and  has 
the  exact  shape  of  the  tooth.  Its  structure  comprises, 
in  the  center,  delicate  connective  tissne,  provided  with 
vessels  and  nerves,  and  on  the  surface  a  layer  of  elon- 
gated cells.  At  the  summit  of  the  follicle,  facing  the 
dentine-germ,  is  the  enamel-germ.  It  is  exactly  ap- 
plied to  the  dentinal-pulp,  which  it  invests  like  a  cap. 


42  TOOTH-GERMS. 

and  is  composed  of  a  small  mass  of  mucous  connec- 
tive tissue,  covered  by  a  layer  of  cylindrical  cells,  and 
joined  to  the  buccal  epithelium  by  the  gubernaculum 
deutis.^  According  to  Monsieur  Magitot,  the  cement- 
organ  manifestly  exists  in  the  foal.  The  base  of  the 
deu tine-germ  has  been  found,  but  it  disappears  rapidly 
after  having  performed  its  function. 

'^Development  of  the  Dental  Follicle. — On  the  free 
borders  of  the  maxillae,  the  epithelium  of  the  buccal 
mucous  membrane  forms  an  elongated  eminence — the 
dental  ridge.  Below  this  ridge  the  epithelium  consti- 
tutes a  bud,  which  develops  in  size,  and  is  sunk  in  the 
mucous  membrane.  This  is  the  enamel-germ.  It  has 
a  layer  of  cylindrical  cells  on  its  deep  surface,  and  in 
its  center  are  round  cells.  After  a  certain  time  it  is 
only  joined  to  the  epithelium,  as  already  said,  by  a  very 
thin  line  of  cells,  the  guheryiaculum  dent  is.  While  this 
enamel-germ  grows  downward,  it  covers,  by  its  base,  a 
connective  bud  which  rises  from  the  mucous  derma. 
The  two  buds  are  reciprocally  adapted  to  each  other, 

*  Concerning  the  gubernaculum  dentis  Prof.  C.  S.  Tomes  says 
("  Dental  Anatomy,"  p.  135):  "  Another  structure,  once  thouglit 
to  be  important,  but  now  known  to  be  a  mere  bundle  of  dense 
fibrous  tissue,  is  the  '  gubernaculum.'  The  permanent  tooth 
sacs,  durinor  their  growth,  have  become  invested  by  a  bony  shell, 
whicli  is  complete,  save  at  a  point  near  their  apices,  where  there 
is  a  fora'men.  Through  this  foramen  passes  a  thin  fibrous  cord, 
very  conspicuous  when  the  surrounding  bone  is  broken  away, 
which  is  called  the  gubernaculum,  from  the  notion  entertained 
by  the  older  anatomists  that  it  was  concerned  in  directing-  or 
effecting  the  eruption  of  the  tooth.  The  guberuacula  of  the 
front  permanent  tooth  sacs  perforate  the  alveolus  and  blend  with 
the  gum  behind  the  necks  of  the  corresponding  milk  teeth, 
those  of  the  bicuspids  uniting  with  the  periosteum  of  the  alveoli 
of  their  deciduous  predecessors." 


THE  DENTINE-GERM  TOOTH-SHAPED.  43 

and  around  them  the  connective  tissue  condenses  and 
gives  rise  to  the  walls  of  the  follicle.  It  will  therefore 
be  seen  that  the  enamel-organ  is  a  dependency  of  the 
epithelium,  and  the  dentine-organ  a  production  of  the 
mucous  derma. 

^'Formation  of  tlie  Dentine,  Enamel,  and  Cement. — 
As  before  said,  the  germ  of  the  dentine  has  exactly  the 
form  of  the  future  tooth;  consequently  the  dentine 
which  arises  from  its  periphery  presents  the  shape  of 
a  tooth  also.  The  dentine  and  enamel  are  developed 
by  the  modification  of  the  elements  situated  at  the 
surface  of  their  germs.  The  dentine  is  constituted  of 
the  cells  of  the  germ,  which  send  out  ramifying  and 
communicating  prolongations— the  dentinal  fibers — 
and  by  an  int-^rcellular  substance,  which  is  impreg- 
nated with  calcareous  matter,  and  which,  being  molded 
around  the  fibers,  forms  canalicnli.  The  enamel  is 
derived  from  the  deep  cells  of  its  germ,  which  are 
elongated  and  prism-shaped,  and  are  calcified  in  be- 
coming applied  to  the  surface  of  the  dentine.  The 
cement  is  developed  at  the  expense  of  the  walls  of  the 
follicle,  according  to  the  mode  of  ossification  of  the 
connective  tissue. 

^'Eruption. — As  the  dentine  is  formed,  the  tooth 
increases  in  length  and  presses  the  enamel-germ  up- 
ward. The  latter,  constantly  compressed,  becomes 
atrophied,  and  finally  disappears  when  the  tooth  has 
reached  the  summit  of  the  follicle.  In  the  same  way 
the  young  organ  pierces  the  dental  follicle  and  gum 
and  makes  its  eruption  externally. 

'^Such  is  the  mode  of  the  development  of  the  tem- 
porary teeth,  and  the  permanent  ones  are  formed  in  the 
same  manner.  During  the  development  of  the  germ 
of  the  temporary  tooth,  a  bud  is  seen  detaching  itself 


44  TOOTH-GEEMS. 

from  this  germ  and  passing  backward,  to  serve,  at  a 
later  period,  in  formnig  tlie  permanent  tooth." 

Ill  another  part  of  his  work  Prof  Chanveau  says: 

"The  follicle  in  which  the  incisor  teetli  are  devel- 
oped shows  only  two  papillse.  One,  for  the  secretion 
of  the  dentine,  is  lodged  in  the  internal  cavity  of  the 
tooth,  and  is  hollowed  into  a  cup-shape  at  its  free  ex- 
tremity; the  other  is  contained  in  the  external  cul-de- 
sac." 

In  describing  the  simplicity  of  the  structure  of  the 
horse's  canine  teeth  (tushes),  Prof.  Lecoq  sa^'s: 

^'The  disposition  of  t1ie  developing  follicle  is  in  har- 
mony with  the  simplicity  of  their  structure.  At  the 
bottom  there  is  a  simple  and  conical  papilla  for  the 
internal  cavity;  on  the  inner  wall,  a  double  longitu- 
dinal ridge,  on  which  are  molded  the  ridge  and  grooves 
on  the  inner  f  ice  of  the  tooth." 

Prof  William  Youatt's  theory  of  the  development 
of  horses'  teeth  is  unique.  He  is  probably  correct 
about  the  bones  or  processes  being  separate,  and  his 
claim  that  they  are  solidified  by  the  cement  is  certainly 
philosophical ;  but  he  differs  from  all  other  authorities 
about  the  enamel  completing  the  formation  of  the 
tooth,  for  it  is  a  well-known  fact  that  a  virgin  tooth 
is  enveloped  by  cement  (its  protecting  varnish),  which 
wears  off  as  soon  as  the  tooth  is  brought  into  use.  He 
says  ('^TheHorse,"p.  223): 

"A  delicate  membranous  bag,  containing  a  jelly-like 
substance,  is  found  in  a  little  cell  within  the  jawbone 
of  the  unborn  animal.  It  assumes  by  degrees  the 
shape  of  the  tooth,  and  then  the  j.dly  begins  to  change 


GREAT  USE  OF  THE  CEMEHT.  45 

to  bony  matter.  A  hard  and  beautiful  crystallization 
is  formed  on  the  membrane  without,  and  so  we  have 
the  cutting  tooth  covered  by  its  enamel. 

"  In  the  formation  of  the  grinders  there  are  origin- 
ally five  membranous  bags  in  the  upper  jaw  and  four 
in  the  lower.  The  jelly  in  thc-m 
gives  place  to  bony  matter, 
which  is  supplied  by  little  ves- 
sels, and  which  is  represented 
by  the  darker  portions  of  the 
cut  with  central  black  spots. 
Tlie  crystalhzation  of  enamel 
may  be  traced  around  each  of  the  bags,  and  there 
would  be  five  distinct  bones  or  teeth  but  for  the  fact 
tliat  a  third  substance  is  now  secreted.  (It  is  repre- 
sented by  the  white  spaces).  It  is  a  powerful  cement, 
and  through  its  agency  the  bones  are  united  into  one 
body,  thus  making  one  tooth  of  tiie  five.  This  being 
done,  another  coat  of  enamel  spreads  over  the  sides, 
but  not  the  top,  and  the  tooth  is  completed." 

Dr.  Robley  Dunglison's  theory  of  the  development 
of  the  human  teeth  is  in  principle  the  same  as  Prof. 
Youatt's  theory  regarding  those  of  the  horse.  In  his 
"Medical  Dictionary,"  article  "teeth,"  he  says: 

"The  incisor  and  canine  teeth  are  developed  by  a 
single  pomt  of  ossification,  the  lesser  molars  by  two, 
and  the  larger  by  four  or  five." 

Surgeons  M.  H.  Bouley  and  P.  B.  Ferguson  believe 
that  the  teeth  are  the  combined  product  of  the  secre- 
tion of  the  |)ulp  and  of  the  membrane  vvdiich  lines  the 
alveolar  cavities.  They  say  that  the  question  as  to 
whether  the  sensibility  of  the  teeth  is  inherent  in  the 
dental  substance  itself,  or  resides  exclusively  in  the 


46  TOOIH-GEKMS. 

pulp,  is  a  pliYsiological  point  of  which  a  satisfactory 
soiution  remains  to  be  given. "^ 

*  Of  tlie  development  of  teetli  in  the  human  fetus  Monsieur 
E.  Magitot  says  ("  Comtes  Rendus,"  1874):  "Seccnth  Week — 
The  epithelial  eminence  and  epithelial  inflection  of  Kolliker 
only  may  be  scan  at  the  edge  of  the  jaw.  The  superior  maxil- 
lary and  intermaxillary  bones  are  not  united,  and  the  inferior 
maxillary  arch  contains  Meckel's  cartilage  only,  without  any 
trace  of  bone.  The  epithelial  bands  (enamel-organs)  are  succes- 
sively formed  in  the  order  of  their  designation.  Ninth — Tiie 
dentine  bulb  appears  in  juxtaposition  with  the  downward  ex- 
tremity'of  sthe  enamel -organ.  This  stage  occurs  nearly  simul- 
taneously for  the  whole  series  of  temro.c:./  follicles.  Tenth — 
The  wall  of  the  follicle  detaches  itself  from  the  base  of  the  bulb 
and  rises  up  its  sides.  Fifteenth — The  epithelial  band  begins 
its  transformation  into  an  enamel-organ.  The  enamel-germ  of 
the  first  2)ermnnent  molar  may  now  be  seen  springing  from  the 
epithelial  inflection.  Sixteenth — The  wall  of  the  follicle  is 
closed.  The  epithelial  band  is  broken,  and  the  follicle  thencefor- 
ward has  no  connection  with  the  surface  epithelium.  The  epi- 
thelial bands  of  the  permanent  teeth,  which  are  derived  from  the 
necks  of  the  enamel-organ  of  tlie  corresponding  deciduous  teeth, 
appear.  S^'venteenth — Appearance  of  the  cap  of  dentine  of  the 
central  and  lateral  incisors  ;  also  the  bulb  of  the  first  permanent 
molar.  Eighteenth — Appearance  of  the  dentine  caps  of  the  first 
and  second  molars  ;  also  the  wall  of  the  follicle  of  the  perma- 
nent mo^ar.  Ticentieth—E.\o^\\t  of  the  dentine  caps  of  the  cen- 
tral incisor,  lateral  incisor,  and  canine,  .059 ;  first  and  second 
molars,  .089.  Appearance  of  dentine  organ  of  permanent  teeth, 
and  inclosure  of  wall  and  rupture  of  l)and  of  first  molar.  Tirenti/- 
jlfth — Dentine  caps,  .07,  .054.  The  permanent  follicle  walls, 
which  appeared  after  the  twenty-first  week,  liave  acquired  a  cer- 
tain distinctness.  2\ceiity-eighth — Dentine  caps,  .093,  .078.  The 
epithelial  germs  of  the  permanent  follicles  begin  their  transfor- 
mation into  enamel-organs;  dentine  cap  first  molar,  .003  to  .007. 
Thirty-sccoud — Dentine  caps,  .113,  .093.  The  first  permanent 
molar  cusps,  which  form  upon  tlie  several  apices  of  the  dentine 
organ,  have  coalesced.  Thirti/sixth— Dentine  caps,  .118,  .109; 
permanent  molar.  .004  to  .039.  Th:'rt7/-ninth— -Dentine  caps, 
.136,  .lis  ;  permanent  molar,  .039  to  .07S.  The  permanent  follicle 
walls  close.     The  dentine  caps  appear  one  month  after  birth.'* 


CHAPTER    II. 

THE  TEMPORARY   DENTITIOIf. 

Twelve  Incisors  and  Twelve  Molars, — Why  the  Incisors  are 
called  "  Nippers." — The  Treatment  of  Foals  Affects  Teeth- 
ing.— Roots  of  Milk  Teeth  Absorbed  by  the  Permanent. 
—The  Tushes. 

The  foaFs  temporary  teeth  (known  also  as  milk  or 
deciduous  teeth)  are  adapted  in  size  and  number  to 
the  capacity  of  the  jaws  and  the  amount  and  nature 
of  the  mastication  required  for  its  sustenance.  There 
are  only  twenty-four  temporary  teeth  functionally  de- 
veloped. They  consist  of  twelve  incisors  or  nippers* 
and  twelve  molars  or  grinders,  six  above  and  six  below 
of  each  kind.     The  dental  formula  is  expressed  thus : 

Incisors,  f — |;  molars,  f — 1=24, 

According  to  Veterinary  Dentist  C.  D.  House,  who 
says  the  care  and  treatment  of  foals  will  affect  the 
growth  of  their  teeth  as  much  as  they  will  their  gen- 

*  Horsemen  call  the  incisor  teeth  "Nippers/.'  The  word  ex- 
presses the  office  they  perform,  to  wit,  nipping-  grass,  as  we!l  as 
the  word  "grinder"  does  in  the  case  of  the  molars — grinding 
corn.  They  call  the  first  pair  of  incisors  "central  nippers,"  or 
"centrals,"  one  being  on  either  side  of  the  median  line;  the 
second  pair  are  the  "  dividers,"  for  they  stand  between  the  first 
and  third  pairs;  the  third  pair  are  called  the  "corners,"  from 
their  forming  the  points  of  the  cr&scent-like  figiu-e. 


48  THE   TEMPORARY    UE^s'TITIOX. 

eral  development,  the  foal  lia^  no  teeth  at  birtli,  Ka- 
ture  providing  a  membrane-like  cover  for  the  incisors 
as  well  as  the  hoofs.  In  two  or  three  days,  however, 
the  molars  are  all  cut.  The  incisors  are  cut  in  pairs, 
two  above  and  two  below.  The  first  pair  protrude  in 
from  three  to  eight  days,  and  attain  their  growth  in 
about  two  months.  The  second  pair  are  cut  when  the 
foal  is  five  or  six  weeks  old.  They  also  attain  their 
growth  in  about  two  months.  The  time  of  cutting  the 
third  pair  varies.  In  some  foals  the\'  appear  as  early 
as  the  sixth  month ;  in  others  as  late  as  the  ninth. 
They  attain  their  growth  in  about  three  months.* 

The  milk  teeth  are  smaller  and  whiter  and  have 
more  distinct  necks  than  the  permanent.  Their  shin- 
ing, milky-white  color,  M,  Chauveau  says,  is  due  to 
the  thinness  or  absence  of  the  cement,  their  crowns 
being  finely  striated  (not  cannular)  on  the  anterior 
face,  and  their  growth,  unlike  the  permanent  teeth, 
ceasing  when  they  begin  to  be  used.f 

"  M.  Rousseau  assigns  from  the  seventh  to  the  tenth  month 
as  the  period  of  the  completion  of  the  first  or  colt's  mouth  den- 
tition. Tlie  deciduous  incisors  have  thinner  and  more  trenchant 
crowns  than  the  permanent. — Owen, 

\  The  absorption  of  the  roots  of  the  milk  teeth  bv  the  per- 
manent would  tend  to  prevent  the  coniiuuous  growth  of  the 
former ;  but  the  real  cause  appears  to  be  that  continuous  growth 
is  contrary  to  their  nature.  As  the  roots  are  conijicsed  of 
cement  (except  the  dentine  lining  the  pulp  cavity),  and  as 
they  are  absorbed,  it  naturally  follows  that  much  of  the  cement 
surrounding  the  crowns  of  the  permanent  teeth  is  derived  from 
them  (cement  from  cement),  thus  lesseninrr  the  drain  on  the 
permanent  tooth  pulps,  which  are  all  the  better  able  to  supply 
cement  for  the  roots  of  the  permanent  teeth.  The  scarcity  of 
cement  on  the  crowns  of  the  milk  teeth  is  probably  owing  to 
the  fact  that  they  had  no  cement  to  absorb.  The  evil  of  extract- 
inor  healthy  milk  teeth  is  obvious^ 


SHED   OR  ABSORBED.  49 

The  incisors,  which  stand  in  an  almost  upright 
position,  are  smooth  and  rounded  on  the  outer  sur- 
face, but  grooved  on  the  inner.  Their  average  length, 
including  the  root,  is  about  an  inch,  their  width 
about  half  au  inch.  The  molars  are  about  an  inch 
and  a  quarter  in  length,  and  nearl}^  an  inch  in  long 
(antero-posterior)  diameter.  The  short  (transverse) 
diameter  of  tlie  upper  molars,  which  is  about  three- 
fourths  of  an  inch,  exceeds  that  of  the  lower  nearly  a 
half.  Surgeon  John  Hughes  says  that  in  proportion 
to  their  length  the  breadth  *  of  the  temporary  teeth  is 
greater  than  the  permanent.  When  first  cut  the  in- 
cisor teeth  are  very  sharp ;  the  outer  edges  are  higher 
than  the  inner,  the  slant  resembling  that  of  a  chisel. 
A  little  wear,  however,  dulls  the  teeth,  and  brings  the 
edges  to  a  common  level.  The  contrast  between  the 
edges  of  the  corner  incisors,  however,  is  distinct  for 
some  time,  the  outer  edge  wearing  off  slowly. 

There  is  a  marked  contrast  in  the  appearance  of  the 
incisors  at  the  age  of  one  year  and  about  the  close  of 
the  second.  At  the  former  period  they  look  new  and 
fresh,  standing  close  together,  while  at  the  latter  they 
not  only  look  old  and  worn,  but  the  development  of 
the  jaws  has  caused  them  to  stand  apart.  Their  nar- 
row necks  are  also  conspicuous  at  two  years  of  age. 

The  incisors  are  shed  in  the  order  in  which  they  are 
cut.  Nature  provides  them  as  they  are  needed,  and 
takes  them  away  so  as  to  cause  the  least  inconvenience 
to  the  foal.  During  the  shedding  of  the  central  inci- 
sors foals  have  the  use  of  the  dividers  and  corners. 
The  permanent  centrals  are  ready  for  use  before  the 
dividers  are   shed,  and   the   permanent   dividers  are 

*"  Breadth  is  antero-posterior  diameter;  thickness  is  trans- 
verse diameter." — B.  Owen 
3 


50  THE  TEMIOEAUY   DEXTITIOI^. 

ready  before  tlie  corners  are  shed.  However,  during 
the  shedding  periods,  particularly  that  of  the  central 
teeth,  foals  experience  more  or  less  difficulty  in  graz- 
ing ;  but  if  they  are  given  a  moderate  quantity  of  soft, 
green  food,  their  health  will  not  be  impaired,  nor  will 
they  lose  much  flesh. 

The  central  incisors  are  shed  when  the  foal  is  about 
two  years  and  a  half  old,  the  dividers  at  three  and 
a  half  or  four,  and  the  corners  at  four  and  a  half  or 
live. 

The  molars,  which  Prof.  Richard  Owen  says  sooner 
begin  to  develop  roots  than  the  permanent,  are  shed 
with  even  less  inconvenience  to  the  foal  tlian  the  in- 
cisors. The  fourth  grinder,  the  first  permanent  tooth 
cut,  is  ready  for  use  before  the  first  temporary  molar 
is  shed,  and  the  fifth  and  sixth  are  ready  before  the 
second  and  third  are  shed.  The  time  of  shedding  the 
twelve  teeth  varies  somewhat,  and  the  falling  off  of 
the  "caps"  of  the  uppers  will  precede  those  of  the 
lower  teeth  several  weeks.  The  caps  are  all  that  is 
left  of  the  temporary  molars,  their  roots  and  perhaps 
a  small  part  of  their  bodies  having  been  absorbed  by 
the  permanent.  In  most  cases  fully  four-fifths  of 
the  crowns  are  worn  off  by  attrition.  Thus,  when 
Nature  is  let  alone,  the  temporary  teeth  are  absorbed 
rather  than  shed;  but  when  a  shell  is  loose  and  in  the 
way,  it  does  no  harm  to  remove  it.  The  first  molar  is 
shed  about  the  end  of  the  second  year,  the  second 
about  the  end  of  the  third,  and  the  third  about  the 
end  of  the  fourth. 

Surgeon  W,  A.  Cherry  says  that  the  shedding  of  the 
teeth  usually  occurs  in  the  Spring.  There  is,  he  says, 
a  sufficient  interval  of  time  between  the  shedding  of 
the  upper  and  lower  molars  for  the  new  teeth  in  the 


UNrUXCTIO:N"ALLY  DEVELOPED   CAXIXES.  51 

upper  jaw  to  meet  the  old  ones  in  the  lower;  sametimes 
the  respective  teeth,  Avhen  the  caps  fall  ofr,  are  not  more 
than  the  sixteenth  of  an  inch  apart.  He  also  says  that 
as  the  temporary  teeth  wear  down  they  become  less 
and  less  dense. 

AVhile,  as  before  said,  it  does  no  harm  to  remove 
loose  shells,  the  punching  out  of  a  pair  of  incisors, 
which  is  sometimes  done  for  the  purpose  of  deception, 
frequently  causes  serious  injury  to  the  permanent 
pair  (which  should  absorb  the  temporary,  and  fill  the 
space  that  has  become  too  large  for  it),  not  to  mention 
the  interference  with  grazing.  The  temporary  teetli  are 
often  l)roken  off  at  the  neck  and  the  sockets  injured; 
this  sometimes  causes  the  permanent  to  grow  irregu- 
larly, which  ill  the  case  of  the  horse  is  a  very  serious 
matter,  for  if  the  permanent  teeth  do  not  meet,  and  are 
consequently  not  worn  off  by  attrition,  their  growth, 
which  continues  throughout  life,  will  cause  trouble. 
There  are  cases,  however,  such  as  abnormal  growths, 
accidents,  &c.,  in  which  it  is  necessary  to  remove  the 
temporary  tooth,  but  the  forceps  only  should  be  used. 
When  the  teeth  have  been  removed  for  the  purpose  of 
deception,  the  object  is  to  make  it  appear  that  they 
have  been  shed,  and  that  the  animal  is  older  than  it 
really  is. 

Veterinary  authors,  as  a  rule,  do  not  mention  the 
temporary  tushes.  A  few  odontologists,  however,  have 
described  them.  Prof.  Owen  ('-Odontography,"  vol.  i, 
p.  580)  says  ''the  small  deciduous  canine"  is  cut  about 
the  sixth  month,  at  the  time  the  third  or  corner  inci- 
sors are  cut.  The  lower  tush,  owing  to  its  diminutive 
size,  and  its  being  so  close  to  the  incisor,  'Ms  shed 
almost  as  soon  as  the  crown  of  the  contiguous  incisor 
is  in  full  place,  being  carried  out  by  the  same  move- 


52  THE  TELIPO.IARY   DEIS'TITIOJf. 

mont."  Bojanns,*  Prof.  Owen  says,  first  "drew  the 
attention  of  veterinary  authors  to  it  by  his  memoir 
'De  Dentibus  Caninis  Caducis/  &c.  Bojanus  never 
found  the  lower  deciduous  canine  retained  beyond  the 
first  year.  The  deciduous  canine  of  the  upper  jaw, 
being  developed  at  a  short  distance  behind  the  incisors, 
is  less  disturbed  by  the  eruption  of  the  outer  incisor, 
but  is  nevertheless  siied  in  the  course  of  the  second 
year.  The  deciduous  canines  appear  from  Camper's f 
observations  to  retain  their  place  longer  in  the  zebra 
than  in  the  horse." 

Monsieur  Lecoq  says: 

"  The  canine  teeth  are  not  shed,  and  grow  but  once. 
Some  veterinarians,  and  among  them  Forthomuie  and 
Kigot,  witnessed  instances  in  which  they  were  replaced ; 
but  the  very  rare  exceptions  cannot  make  us  look  upon 
these  teeth  as  liable  to  be  renewed.  We  must  not, 
however,  confound  witli  these  exceptionable  cases  the 
shedding  of  a  small  spicula  or  point,  which,  in  the 
majority  of  horses,  precedes  the  eruption  of  the  real 
tusks.'' 

Prof.  C.  S.  Tomes  says: 

"  The  milk  teeth  of  all  the  ungulata  are  very  com- 
plete, and  are  retained  late.  They  resemble  the  per- 
manent teeth  in  general  character,  but  the  canines  of 
the  horse,  as  might  have  been  expected — their  greater 
development  in  the  male  being  a  sexual  character — are 
rudimentary  in  the  milk  dentition." 

*  "  Nova  Acta  Nat.  Curios.,  torn,  xii,  part  ii,  p.  697.     1825." 
f  "  CEuvres  de  Pierre  Camper.    Paris,  X805." 


CHAPTER    III. 

THE   PERMANENT  DENTITION. 

Distinction  between  Premolars  and  Molars. — The  Bow-like  In- 
cisors.— Contrasts  between  the  Upper  and  Lower  Grinders, 
and  the  Rows  formed  by  them. — The  Incisors  saved  from 
Friction. — Horsss'  Teeth  compared  with  those  of  other  An- 
imals.— Measurements. — Time's  Changes. — Growth  during 
Life. 

The  Permanent  Teeth,  owing  to  their  increased  size 
and  number,  are  as  well  adapted  to  the  needs  of  the 
horse  as  the  temporary  are  to  the  foal.  In  the  males 
forty  teeth  are  functionally  developed  ;*  in  the  females 
thirty-six,  the  latter,  as  a  rule,  having  no  canine  teeth. 
However,  their  rudiments  exist  in  the  jaws,  and  some- 
times, especially  in  old  age,  protrude.  Of  the  forty 
teeth  in  the  male  horse  there  are  twelve  incisors,  four 
canines  or  tushes  (also  called  cannon  or  bridle  teeth), 
twelve  premolars,!  and  twelve  molars.  The  dental 
formula  is  expressed  thus : 

L;|-|;  0.,i-{;  P.M.,|-|;  M.,f-|=40. 

*  The  teeth  that  are  not  functionally  developed  are  treated  of 
in  the  chapter  entitled  "Remnant  Teeth." 

f  "  Premolars  are  teeth  in  front  of  the  molars ;  they  usually 
differ  from  them  by  beiu^  smaller  and  more  simple  in  form,  and 
in  most  animals  have  displaced  deciduous  predecessors.  But 
they  are  not  always   smaller  nor  simpler  in  form  [e.  g.,  the 


54  THE   PERMANEI^T  DENTITION". 

The  incisors  and  premolars  absorb  and  replace  the 
entire  temporary  dentition,  except  the  shells  or  caps 
described  in  the  preceding  chapter,  but  the  canines 
and  molars  are  cut  through  the  gums. 

In  veterinary  works,  as  a  rule,  no  distinction  is  made 
between  a  premolar  and  a  molar,  the  twenty-four  back 
teeth  being  called  either  molars  or  grinders.  Prof. 
C.  S.  Tomes  says  the  premolars  and  molars  "are  very 
similar  to  one  another  in  shape,  size,  and  in  the  pat- 
tern of  their  grinding  surface."  There  is  a  difference, 
however,  between  the  respective  teeth,  and  naturalists 
make  a  distinction.  The  premolars  (the  three  first 
back  teeth),  which  replace  the  temporary  molars,-  are 
slightly  larger  than  the  molars  (the  three  last  back 
teeth).  They  have  besides  a  backward  inclination, 
while  the  molars  incline  forward  ;  the  respective  teeth 
are  thus  set  toward  one  another.  Both  kinds  are 
properly  called  grinders. 

The  permanent  teeth  are  cut  in  pairs,  two  in  either 
jaw,  the  upper  teeth  preceding  the  lower  from  one  to 
two  weeks.  In  the  cutting  of  the  canines,  however, 
the  reverse  is  the  rule,  for  the  lower  teeth  precede  the 
upper.  About  a  year's  time  elapses  between  the  cut- 
ting of  the  respective  pairs  of  teeth  ;  that  is,  wdien  the 
central  incisors  are  cut,  it  will  be  about  a  year  before 
the  dividers  will  emerge.  The  rule  is  applicable  to 
the  premolars  and  molars  also,  but  the  case  is  different, 
for  twenty-four  of  these  teeth  have  to  be  cut  during 

horse) ;  nor  do  tliey  always  displace  deciduous  predecessors 
{e.  g..  they  do  not  all  do  so  in  the  marsupials) ;  so  that  this  defi- 
nition is  not  alisolutely  ]n-ecise.  Still,  as  a  matter  of  practice, 
it  is  usually  easy  to  distinguish  the  premolars,  and  the  division 
into  premolars  and  molars  is  useful."— C.  8.  To?ncs,  "Dental 
Anatomy,''  cfr.,  ;?.  ^58. 


TIME  OF  cutti:n'G.  65 

the  same  period  of  time  that  the  twelv^e  incisors  are 
cut.  A  permanent  tooth  attains  its  growth  in  about  a 
year. 

According  to  the  best  autliorities,  the  molar  and 
canine  teeth  are  cut  at  the  following  periods:  The 
first  molars  (in  veterinary  works  they  are  called  the 
fourth,  because  the  three  premolars  come  in  front  of 
them)  are  the  first  permanent  teeth  cut.  The  time  of 
their  cutting  varies,  for  the  foal's  jaws  must  be  suffi- 
ciently developed  to  afl'ord  them  room,  notwithstand- 
ing they  are  usually  the  smallest  of  the  six  back  teeth. 
They  are  cut  about  the  beginning  of  the  second  year, 
and  are  generally  ready  for  use  by  the  time  the  foal  is 
two  years  old.  The  second  molars  are  cut  at  about 
the  age  of  two  years,  and  are  therefore  fully  developed 
by  the  end  of  the  third  year.  The  third  pairs,  the  last 
of  the  molars,  and  consequently  the  most  posterior  of 
all  the  teeth,  are  sometimes  cut  as  early  as  the  third 
year,  in  v/hich  case  they  would  be  developed  by  the  end 
of  the  third  or  the  beginning  of  the  fourth  year.  The 
time,  however,  may  be  prolonged  six  months  or  more. 
The  canine  teeth  (tushes)  emerge  at  or  near  the  be- 
ginning of  the  fourth  year.^ 

The  time  of  the  appearance  of  the  incisors  and  pre- 
molars has  already  been  indicated  in  the  preceding 
chapter.  However,  the  following  extract  from  Prof. 
Owen's  '*  Odontography"  is  appropriate  in  this  place, 
as  it  throws  further  light  on  the  subject,  and  to  some 
extent  agrees  with  the  dates  already  given : 

"  The  first  true  permanent  molar  appears  between 
the  eleventh  and  thirteenth  months.     The  second  fol- 

*"  For  further  particulars  concprning  the  tushes  the  reader  is 
referred  to  the  siicceedinor  cho^ptcr. 


56  THE  PERMANENT  DENTITION. 

lows  between  the  fourteenth  and  twentieth  months. 
The  crowns  of  the  premolars  and  the  last  true  molar 
are  now  advancing  in  the  closed  sockets  of  reserve. 
The  first  premolar  displaces  the  second,*  and  usually 
at  the  same  time  the  very  small  deciduous  molar,  at 
from  two  years  to  two  years  and  a  half  old.  The  first 
permanent  incisor  rises  above  the  gum  between  two 
years  and  a  half  and  three  years.  At  the  same  period 
the  second  premolar  pushes  out  the  third  deciduous 
molar.  The  last  premolar  displaces  the  last  deciduous 
molar  about  the  completion  of  the  fourth  year,  and 
the  appearance  above  the  gum  of  the  last  true  molar 
is  usually  anterior  to  this.  The  second  incisor  pushes 
out  its  predecessor  between  three  and  a  half  and  "four 
years.  The  small  persistent  canine  or  tusk,  contrary 
to  the  usual  rule,  next  follows,  its  development  having 
received  no  check  by  the  retention  of  its  rudimental 
predecessor.  Its  appearance  indicates  the  age  of  four 
years ;  but  it  sometimes  appears  earlier,  rarely  later. 
The  third  incisor  pushes  out  the  deciduous  one  about 
the  fifth  year,  but  is  seldom  completely  in  place  before 
the  horse  is  five  years  and  a  half  old.  The  third  pre- 
molars are  then  usually  on  a  level  with  the  other 
grinders." 

On  the  completion  of  the  fifth  year  a  male  foal  is 
called  a  horse,  a  female  or  filly  foal  a  mare.  The  teeth, 
however,  are  not  all  fully  developed  before  the  sixth 
year,  and  the  roots  of  the  grinders  do  not  begin  to 

*To  prevent  confusion,  it  should  be  nnderstood  that  Prof. 
Owen  calls  the  "very  small  deciduous  molar"  here  referred  to 
the  first  deciduous  molar,  notwithstanding  it  is  not  functionally 
developed.  Hence,  as  it  has  no  successor,  the  first  premolar  dis- 
places the  second  dicid/wus  molar,  the  second  premolar  the  third 
deciduous  molar,  and  the  third  the  fourth. 


THE   li^CISORS  ADAPTED  FOR  GRAZIls"G.  57 

grow  till  about  the  seventh  year,  being,  to  use  Prof. 
Owen's  words,  "implanted  in  the  socket  by  an  undi- 
vided base." 

The  incisor  teeth,  which  will  average  about  two 
inches  and  a  quarter  in  length,  are  characterized  by 
distinct  curvatures,  the  outer  sur- 
face, according  to  Surgeon  John 
Hughes,  forming  a  third  of  a  cir- 
cle, the  inner  a  fifth.  Were  a  string 
drawn  from  the  crown  of  one  of 
these  teeth  to  the  apex  of  the 
root,  the  figure  would  resemble  a 
bow.  The  upper  teeth  are  larger 
than  the  lower,  and  there  is  a  dif- 
ference in  size  of  the  respective 
teeth  in  both  jaws,  the  centrals 
being  larger  than  the  dividers, 
and  the  dividers  larger  than  the 
corners. 

The  incisors  meet  edge  to  edge, 
being  thus  admirably  adapted  for 
the   purposes    of    grazino^,   and   at 

-  p       .  i,T  -*-  ^''rgin  incisor  tooth  ;  pos- 

the  age  oi  six  years  the  bodies  are     tenor  face.- c/wweau. 
nearly  perpendicular  one  to  the  other.     They  form 
nearly  semicircular  figures,  and,  when  the  mouth  is 
closed,  present  a  ronnded  outer  surface. 

"  The  incisors,"  says  Prof.  Owen,  "if  found  detached, 
recent  or  fossil,  are  distinguishable  from  those  of  the 
ruminants  by  their  greater  curvature,  and  from  those 
of  all  other  animals  by  the  fold  of  enamel  which  pen- 
etrates the  body  of  the  crown,  from  its  broad,  flat  sum- 
mit, like  the  inverted  finger  of  a  glove." 

The  fold  of  enamel,  which  is  commonly  called  the 
"mark,"  but  which  is  also  known  as  the  infundibulum, 


58  THE   PERMAN^EXT   DEKTITIOX. 

central  enamel,  &c.,  according  to  Surgeon  J.  Hughes's 
measurements,  penetrates  the  lower  centrals  to  the 
depth  of  from  -|  to  -^^  of  an  inch ;  the  divid- 
ers from  yV  to  f,  and  the  corners  from  -|  to 
f.  It  penetrates  the  upper  centrals  from  1 
inch  and  -^^  to  1  and  ^ ;  the  dividers  from 
1  and  I  to  1  and  J,  and  the  corners  from  | 
to  nearly  1  iuch.  Prof.  Youatt  says  the 
grinders  have  each  two  infundibula,  which 
penetrate  to  their  roots. 

The  following  is  Prof.  A.  Chauveau's  description  of 
the  incisor  teeth  ("The  Comparative  Anatomy  of  the 
Domesticated  Animals/^  Fleming's  trans.,  p.  349) : 

"The  general  form  of  the  incisors  is  that  of  a  tri- 
faced  pyramid,  presenting  an  incurvation  whose  con- 
cavity is  toward  the  mouth.  Tlie  base  of  this  pyra- 
mid, the  crown  of  the  tooth,  is  flattened  before  and 
behind.  The  summit  or  extremity  of  the  fang,  is,  on 
the  contrary,  depressed  on  both  sides.  The  shaft  of 
the  pyramid  presents  at  different  points  of  its  hight,  a 
series  of  intermediate  conformations,  which  are  utilized 
as  indications  of  age,  the  continual  growth  of  the  teeth 
bringing  each  of  them  in  succession  to  the  frictional 
surface  of  the  crown. 

"  Examined  in  a  3^oung  tooth,  but  one  that  has  com- 
pleted its  evolution,  the  free  portion  presents  the  fol- 
lowing characteristics:  An  anterior  face,  indented  by 
a  slight  longitudinal  groove,  which  is  prolonged  to 
the  root ;  a  posterior  face,  rounded  from  side  to  side; 
two  borders,  of  which  the  internal  is  always  thicker 
than  the  external;  and,  lastly,  the  surface  of  friction. 
The  latter  does  not  exist  in  a  tooth  that  has  not  been 
used,  but  in  its  stead  are  two  sharp  margins,  circum- 


THE  TWO  RIXG3  OF  EXAM:EL.  59 

scribing  a  cavity  named  the  external  dental  cavity,  or, 
better,  infitndihulum.  This  cavity  terminates  by  a 
conical  cul-de-sac,  which  descends  more  or  less  deeply 
into  the  snbstance  of  the  tooth.  The  margins  are 
designated  the  anterior  and  posterior.  The  latter,  less 
elevated  than  the  former,  is  cut  by  one  or  more 
notches,  which  are  always  deepest  in  the  corner  teeth. 
It  is  by  the  wear  of  these  margins  that  the  surface  of 
friction  is  formed,  and  in  the  center  of  which  the  in- 
fundibulum  persists  during  a  certain  period  of  time. 

*•  The  root  is  perforated  by  a  single  aperture,  through 
wliich  the  pulp  of  the  tooth  penetrates  into  the  inter- 
nal cavity. 

"In  the  composition  of  the  incisor  teeth  are  found 
the  three  fundamental  substances  of  the  dental  organ. 
The  dentine  envelops  the  pulp  cavity.  Dentine  is  de- 
posited in  this  cavity  after  the  complete  evolution  of 
the  tooth  to  replace  the  atrophied  pulp,  the  yellow  tint 
of  which  distinguishes  it  from  the  dentine  of  the  first 
formation.  It  forms  on  the  table  of  the  tooth  the 
mark  designated  by  Girard  the  dentinal  star. 

"  The  enamel  covers  the  dentine,  not  only  on  its  free 
portion,  but  also  on  the  roots;  it  does  not  extend, 
however,  to  their  extremities.  It  is  doubled  into  the 
external  dental  cavity,  lining  it  throughout;  and  when 
the  surface  of  friction  is  established,  a  ring  of  enamel 
may  be  seen  surrounding  it,  and  an  internal  ring  cir- 
cumscribing the  infundibulum.  The  first  circle  is 
called  the  encircling  enamel,  the  second  the  central 
enamel.  In  the  virgin  tooth  the  central  enamel  is 
continuous  with  the  external  enamel,  and  passes  over 
the  border  wliich  circumscribes  the  entrance  to  the 
infundibulum. 

"  The  cement  is  applied  over  the  enamel  like  a  pro- 


60  THE   PERMAXEiq-T  DEXTITIOK. 

tectin<T  varnish,  but  is  not  everywhere  of  the  same 
thickness.  On  the  salient  portions  it  is  extremely 
thin,  and  the  friction  caused  by  the  food,  the  lips,  and 
the  tongue  soon  wears  it  away  altogether.  It  is  more 
abundant  in  depressed  situations,  as  in  the  longitudi- 
nal groove  on  the  anterior  face  of  the  tooth,  and  par- 
ticularly at  the  bottom  of  the  infundibulum.  The 
quantity  accumulated  in  this  cul-de-sac  is  not,  how- 
ever, ahvays  the  same.  We  have  seen  it  almost  null, 
and  on  the  otlier  hand,  we  possess  an  incisor  unworn, 
or  nearly  so,  in  wdiich  the  cavity  is  almost  entirely 
obstructed  by  it.  We  are  not  aware  that,  up  to  the 
present  time,  any  account  has  been  taken  of  these  dif- 
ferences in  calculating  the  progress  of  wear ;  but  it  is 
manifest  that  they  shorten  or  prolong  the  time  re- 
quired for  the  effacement  of  the  infundibulum." 

The  grinder  teeth,  the  horse's  millstones,  present 
various  and  interesting  contrasts.  They  are  sepa- 
rated from  the  incisors  by  a  space  that  will  average 
about  four  inches  in  extent,  the  sharp-pointed  tushes 
(in  males)  only  intervening.  The  space  between  the 
grinders  and  tushes  is  called  the  diastema  (place  for 
the  bit).  The  upper  grinders,  except  the  first  and 
last,  are  nearly  quadrangular  in  form.  The  first  and 
last,  which  exceed  the  others  about  a  third  of  an  inch 
in  antero-posterior  (front  to  rear)  diameter,  terminate 
in  obtuse  angles,  which  are  far  more  pronounced  on 
the  inner  than  on  the  outer  surface,  thus  affording  the 
tongue  fuller  and  freer  play,  without  the  danger  of  its 
being  lacerated,  as  would  be  the  case  were  the  angles 
sharp.  The  form  of  the  lower  grinders,  with  the  same 
exceptions  in  the  case  of  the  first  and  last,  is  nearly 
rectangular;    their   antero-posterior   diameter  is  the 


THE  HORSE'S   DII^I^ER  TABLES.  61 

same  as  that  of  the  upper  teeth,  but  their  transverse 
diameter  is  nearly  a  half  less. 

The  broad  crowns  of  the  upper  teeth  form  what  are 
called  by  veterinarians  "  tables,"  whereon  the  food  is 
ground  or  kneaded  by  the  narrow-crowned  opposite 
grinders,  the  lateral  movement  of  the  lower  jaw  ena- 
bling the  latter  teeth  to  pa^  over  the  entire  extent  of 
the  former. 

The  crown  surfaces  of  the  upper  and  lower  rows  are 
slanting  instead  of  level,  the  former  slanting  inward, 
the  latter  outward.  The  inclined-planes  are  thus  in 
perfect  opposition,  and  yet  in  perfect  harmony,  for  they 
facilitate  the  lateral  and  semicircular  movement  of  the 
lower  jaw  during  mastication. 

The  figures  formed  by  the  upper  and  lower  rows  of 
grinders,  aside  from  the  difference  in  their  thickness, 
are  very  dissimilar.  The  upper  rows  are  slightly  con- 
cave, and  converge  in  conformity  to  the  narrowing  of 
the  jaws;  the  space  between  the  sixth  grinders  averages 
about  two  inches  and  four-fifths,  while  that  between 
the  first  is  about  two  inches.  The  lower  rows  form 
regular  but  oblique  lines,  which  also  converge,  like  the 
sides  of  a  hopper,  in  conformity  to  the  narrowing  of 
the  jaws,  the  space  between  the  two  sixth  grinders  and 
the  two  first  averaging  respectively  two  inches  and  a 
half  and  one  inch  and  a  half.  Thus,  when  the  mouth 
is  closed,  the  low^er  teeth  in  the  region  of  the  sixth 
grinders  scarcely  cover  a  third  of  the  crown  surface  of 
the  upper  teeth,  while  those  in  the  region  of  the  first 
barely  lap  their  inner  edges.  This  apparent  structural 
defect  is  overcome  by  the  lateral  movement  of  the 
lower  jaw,  which,  owing  to  the  fact  that  it  increases 
in  proportion  to  the  distance  from  its  hinge-like  joint 
in  the  region  of  the  temporal  bone  and  zygomatic 


6^  THE  PERMANENT  DENTITION. 

arch,*  is  greater  in  the  region  of  the  first  grinders 
than  in  that  of  the  sixth.  Therefore  it  will  be  per- 
ceived that  it  is  only  alternately  that  the  rows  are  used 
in  the  performance  of  the  masticatory  function,  and 
that  were  the  grinders  in  exact  apposition  (edge  to 
edge),  the  lateral  and  semicircular  movement  of  the 
lower  jaw  would  be  as  awkward  and  unnatural  in  the 
case  of  the  horse  as  the  same  movement  would  be  in  a 
human  being. 

There  are  still  other  contrasts  between  the  grinders. 
According  to  Surgeons  M.  H.  Bouley  and  P.  B.  Fergu- 
son, the  upper  teeth  are  slightly  convex,  the  lower 
slightly  concave.  Again,  according  to  Charles  D. 
House,  the  outer  surface  of  the  upper  grinders  is  pro- 
vided with  a  coat  of  enamel  twice  as  thick  as  that  of 
the  inner,  while  the , reverse  is  the  case  with  the  lower 
teeth.  There  is  design  in  this  provision  of  Nature 
(notwithstanding  Mr,  House  says  it  is  inexplicable), 
for  the  projecting  edges  receive  that  which  they  re- 
quire, to  wit,  strength  in  proportion  to  their  hight; 
otherwise  they  would  be  easily  broken  off.    As  the 

*  Prof.  Youatt  says :  "  The  brandies  of  tlie  lower  jaw  termi- 
nate in  two  processes,  tlie  coracoid  (beak-like),  and  the  condy- 
loid (rounded).  The  coracoid  passes  under  the  zygomatic  arcli, 
the  temporal  muscle  being  inserted  into  it  and  wrapped  round 
it.  The  condyloid  is  received  into  the  glenoid  (shallow)  cavity 
of  the  temporal  bone,  at  the  base  of  the  zygomatic  arch,  and 
forms  the  joint  on  which  the  lower  jaw  moves.  The  joint  ad- 
mits of  a  hinge-like  motion,  which  is  the  action  of  the  jaw  in 
m]>piiig  the  herbage  and  seizing  the  corn.  The  corn,  however, 
must  be  ground ;  bruising  and  champing  it  are  not  sufficient  for 
the  purposes  of  digestion.  It  must  be  put  into  a  mill.  It  is  put 
into  a  mill,  and  as  perfect  a  one  as  imagination  can  conceive. 
The  construction  of  the  glenoid  cavity  gives  the  required  lateral 
or  grinding  motion." 


THE  GRIKDERS  THEIR  OWK  WHETSTOKES.        63 

lower  edges  have  ouly  about  half  the  liight  of  the  up- 
per, they  do  not  require  more  than  half  the  quantity 
of  enamel  to  strengthen  them.  Another  use  of  this 
unequal  disposition  of  enamel  is  its  tendency,  by  its 
wear,  to  preserve  the  slant  of  the  respective  crown  sur- 
faces. Further,  the  dentine,  which  fills  the  interspaces 
between  the  folds  or  ridges  of  enamel,  being  softer 
than  the  enamel,  wears  out  faster,  thus  keeping  the 
ridges  sliarp.*  The  grinders  are  therefore,  owing  to 
this  "interblending  of  the  dental  tissues,"  their  own 
whetstones  as  well  as  the  horse's  millstones. 

Some  writers,  even  of  the  present  day,  deny  that  the 
enamel  penetrates  to  the  interior  of  the  grinders;  but 
the  fact  that  it  does  was  established  by  John  Hunter 
over  a  century  ago,  and  a  cut  of  a  section  of  a  horse's 
grinder  (slightly  magnified)  showing  the  enamel  folds, 

*  Prof.  R.  Owen  illustrates  the  above  principle  in  tlie  Intro- 
duction to  his  "  Odontoe;raph y,"  pao^e  26.  He  says :  "  It  (the 
enamel)  sometimes  forms  only  a  partial  itivestment  of  the  crown, 
as  in  the  molar  teeth  of  the  iguanodon,  the  canine  teeth  of  the 
hog  and  hippopotamus,  and  the  incisors  of  the  Rodentia.  In 
these  the  enamel  is  placed  only  on  the  front  of  the  tooth,  but  is 
continued  along  a  great  part  of  tlie  invested  base,  which  is  never 
contracted  int6  one  or  divided  into  more  roots,  so  that  the  char- 
acter of  the  crown  of  the  tooth  is  maintained  throughout  its 
extent  as  regards  both  its  shape  and  structure.  The  partial 
application  of  the  enamel  operates  in  maintaining  a  sharp  edge 
upon  the  exposed  and  worn  end  of  the  tooth  precisely  as  the 
hard  steel  keeps  up  the  outer  cutting  edge  of  the  chisel  by  being 
welded  against  an  inner  plate  of  softer  iron." 

Prof.  C.  S.  Tomes,  speaking  of  the  grinder  teeth  of  the  horse, 
says  :  "  As  each  ridge  and  pillar  of  the  tooth  consists  of  dentine 
bordered  by  enamel,  and  the  arrangement  of  the  ridges  and  pil- 
lars is  complex,  and  as,  moreover,  cementum  fills  up  the  inter- 
spaces, it  is  obvious  that  an  efficient  rough  grinding  surface  will 
be  preserved  by  the  unequal  wear  of  the  several  tissues." 


64  THE  PEllMANEi^^T  DEiJTITION. 

may  be  found  in  his  "  Natural  History  of  the  Human 
Teeth." 

The  formation  of  the  enamel  is  thus  described  by 
Prof.  Bouley  and  Surgeon  Ferguson  (^'Veterinarian," 
1844) : 

"  In  the  grinder  teeth  the  enamel  may  be  said  to 
resemble  a  little  ribbon,  which  forms,  in  refolding 
many  times  upon  itself  in  the  interior  of  the  tooth,  a 
succession  of  undulating  planes,  and  constitutes  the 
hard  external  envelop  of  the  cubic  mass  of  the  organ. 
An  idea  of  this  disposition  may  be  formed  on  examin- 
ing a  tooth  which  is  not  yet  cut,  but  which  is  ready  to 
be  cut.  Those  that  have  been  worn,  present  on  their 
crowns,  besides  the  undulating  lines  of  the  enamel 
envelop,  a  succession  of  reliefs,  salient  and  sinuous,  of 
the  substance  of  the  enamel,  which  are  nothing  else 
than  the  free  borders  of  this  folded  ribbon.  It  is  in 
the  intervals  of  the  folds  of  enamel  that  is  deposited 
the  ivory-colored  substance  (dentine),  which  renders 
the  tooth  a  solid  mass  when  it  has  attained  its  full 
growth." 

Prof.  Piichard  Owen,  one  of  the  first  odontologists 
of  the  age,  in  whose  numerous  works  descriptions  of 
many  kinds  of  teeth  may  be  found,  has  paid  a  fair 
share  of  attention  to  the  study  of  horses'  teeth,  both 
recent  and  fossil.  His  description  of  the  grinders  and 
comparisons  with  the  teeth  of  other  animals  are  too 
interesting  to  be  omitted  here,  and  render  any  apology 
for  the  few  repetitions  of  facts  already  given  unneces- 
sary.    He  says  ("  Odontography,"  vol.  i,  p.  572) : 

"The  horse  will  yield  us  the  first  example  of  the 
dentition  of  the  hoofed  quadrupeds  with  toes  in  un- 


ANOPLOTHERES,  RUMIN^AXTS,  AND  TAPIRS.        65 

even  number,  because  it  offers  in  this  part  of  its  organ- 
ization some  transitional  features  between  the  dental 
characters  of  the  typical  members  of  the  isoclactyle 
and  of  those  of  the  anisodactyle  ungulata. 

"All  the  kinds  of  teeth  are  retained  and  in  almost 
normal  numbers  in  both  jaws,  with  as  little  unequal 
or  excessive  development  as  in  the  anoplothere,*  but 
the  prolongation  of  the  slender  jaws  carries  the  canines 
and  incisors  to  some  distance  from  the  grinders,  and  cre- 
ates a  long  diastema,  as  in  the  ruminants  f  and  tapirs.  J 

*  "The  anoplothere  was  one  of  tlie  earliest  forms  of  hoofed 
quadrupeds  introduced  upon  the  surface  of  this  earth,  and  it  is 
characterized  by  the  most  complete  system  of  dentition.  It  not 
only  possessed  incisors  and  canines  in  both  jaws,  but  they  were 
so  equally  developed  that  they  formed  one  unbroken  series  with 
the  premolars  and  molars,  which  character  is  now  found  only 
in  the  human  species.  The  dental  formula  is  r  I.,  3—3,  3—3  ; 
C,  1-1, 1-1 ;  P.  M.,4-4.  4-4;  M.,  3-3,  3-3=44.  The  An- 
oplothere Commiine  was  the  size  of  an  ass,  and,  with  the  other 
species  of  the  extinct  genus,  had  a  cloven  hoof,  like  the  Rumi- 
nants, but  the  division  extended  throufjrh  the  metacarpus  and 
metatarsus.  The  anoplothere  was  an  animal  of  aquatic  habits, 
and  had  a  very  long-  and  strong  tail,  which  Cuvier  conjectures 
to  have  been  used  like  that  of  the  otter  in  swimming." — Oice?i. 

f  "  The  ordinary  dental  formula  of  the  Ruminantia  is  :  I. 
(upper  jaw),  0-0,  (lower  jaw),  3—3  ;  C,  0—0,  1—1 ;  P.  M.,  3-3, 
3—3 ;  M.,  3—3,  3—3=32.  The  antelopes,  the  sheep,  and  the 
ox,  which  are  collectively  designated  the  'hollow-homed  '  rumi- 
nants, present  this  formula.  It  likewise  characterizes  many  of 
the  '  solid-horned '  ruminants,  or  the  deer  tribe,  the  exceptions 
having  canine  teeth  in  the  upper  jaw  in  the  male  sex,  and  some- 
times also  in  the  female,  thoug'h  they  are  always  smaller  in  the 
latter.** — Owen. 

X  "  The  dental  formula  of  the  tapir  is  :  I.,  3—3. 3—3 ;  C,  1  — 1, 
1-1  ;  P.  M.,  4-3,  4-3  ;  M.,  3-3,  d~d^ 42.''— Owen. 

It  is  noteworthy  that  the  dentition  of  the  tapir  corresponds 
precisely  in  number  with  that  of  the  horse,  provided  the  latter's 


66  THE   PERMAK^ENT  DENTITIOJSr. 

"The  upper  grinder  teeth  present  a  modification  of 
the  complex  structure  intermediate  between  the  ano- 
plotherian  and  ruminant  patterns.  The  crown  is 
cubical,  but  is  impressed  on  the  outer  surface  by  two 
wide  and  deep  longitudinal  channels.  It  is  penetrated 
from  within  by  a  valley,  which  enters  obliquely  from 
behind  forward.  This  is  crossed  by  two  crescentic 
valleys,  which  soon  become  insulated,  as  in  the  camel;* 
but  a  large  internal  lobe,  at  the  end  of  the  oblique  val- 
ley, presents  more  of  the  anoplotherian  proportions 
than  is  shown  by  any  ruminant.  It  is  at  first  distinct ; 
but  although  it  soon  becomes  confluent  with  the  ante- 
rior lobe  in  the  existing  species  of  the  horse,  it  con- 
tinued distinct  much  longer,  and  with  more  of  the  con- 
ical or  columnar  form,  in  the  primigefiial  horse  of  the 
miocene  tertiary  period. 

"The  grinder  teeth  of  the  horse,  Cuvierf  remarks, 

Remnant  teeth  are  counted  ;  and,  besides,  the  odd  teeth  in  "both 
animals  appear  in  the  upper  jaw.  Prof.  T.  H.  Huxley  says  : 
"  Deei>en  the  valley,  increase  the  curv^ature  of  the  (outer)  wall 
and  lam'inse  (transverse  ridges);  give  the  latter  a  more  directly 
backward  slope;  cause  them  to  develop  accessory  ridges  and 
pillars,  and  the  upper  molars  of  the  tajnr  will  pass  through  the 
structure  of  that  of  the  rhinoceros  to  that  of  the  horse." 

*"The  dental  formula  of  the  camel  is:  I.,  1-3,1—3;  M., 
6—0,  6—6=32.  The  anterior  molars  are  conical:  They  are 
separated  from  the  posterior  molars,  and  are  sometimes  regarded 
as  canines.  The  up.per  incisors  are  also  conical,  compressed, 
somewhat  curved,  resembling  canines,  and  are  used  for  tearing 
up  the  hard  and  strong  plants  of  the  desert,  on  which  the  ani- 
mal usually  feeds." — American  Cyclopedia.     . 

f  A  French  naturalist.  Died  May  13, 1832.  "  He  is  regarded 
as  the  founder  of  the  science  of  comparative  anatomy,  and  his 
knowledge  of  the  science  was  such  that  a  bone  or  a  small  frag- 
ment of  a  fossil  animal  enabled  him  to  determine  the  order,  and 


THE  HORSE  AND  THE   RHINOCEROS.  67 

have  a  closer  analogy  with  those  of  the  rhinoceros* 
than  miglit  at  first  be  supposed.  The  anterior  cres- 
centic  enamel  represents  the  termination  of  the  prin- 
cipal or  oblique  valley,  which  is  cut  off  by  a  bridge  of 
dentine  analogous  to  that  in  the  leptorhine  rhinoceros. 
The  posterior  crescentic  island  is  a  further  develop- 
ment of  the  folds  in  the  rhinoceros'  molar,  but  is  much 
earlier  insulated  in  the  horse. 

''•In  the  lower  jaw  the  same  analogies  maybe  traced. 
The  teeth,  on  the  outer  side,  are  divided  into  two 
convex  lobes  by  a  median  longitudinal  fissure;  on  the 
inner  side  they  present  three  principal  unequal  convex 
ridges,  and  an  anterior  and.  posterior  narrower  ridge. 
The  crown  of  the  grinder  is  penetrated  from  the  inner 
side  by  deeper  and  more  complex  folds  than  in  the 
anoplothere,  and  still  more  so  than  in  the  rhinoceros 


even  genus,  to  which  it  belonged.  The  time  of  Cnvier  marks 
the  opening  of  a  new  epoch  in  comparative  anatomy.  He  ap- 
plied this  science  to  natural  history,  physiology,  and  to  the  study 
of  fossils  The  first  edition  of  "Lecons  d'Anatomie  Comparee" 
appeared  about  the  beginning  of  the  present  century,  and  the 
second  was  the  last  work  upon  which  Cuvier  labored.  For 
more  than  thirty  years  he  had  collected  an  immense  amount  of 
facts  and  materials,  which  are  partly  embodied  in  this  book.  It 
is  a  monument  of  patient  industry,  a  model  in  arrangement,  and  ^ 
a  mine  of  knowledge,  of  whicii  all  observers  since  have  availed 
themselves. " — American  Cyclopedia. 

*  "  The  essential  characteristics  of  the  dentition  of  the  genus 
rhinoceros  are  to  be  found  in  the  form  and  structure  of  the 
molar  teeth.  They  differ  essentially  from  those  of  the  horse  by 
being  implanted  by  distinct  roots.  The  normal  dental  formula 
of  the  molar  series  is:  P.  M.,  4-4,  4-4;  M.,  3-3,  3-3=28. 
There  are  no  canines.  As  to  the  incisors,  the  species  vary,  not 
only  in  regard  to  their  form  and  proportions,  but  also  their  ex- 
istence."— Owen. 


68  THE   PERMANENT  DENTITION. 

and  paleothere.*  The  anterior  valley  between  the  nar- 
row ridge  and  the  first  principal  internal  column  ex- 
pands into  a  subcrescentic  fold.  The  second  is  a  short, 
simple  fold,  and  terminates  opposite  that  which  pene- 
trates the  tooth  from  the  outer  side.  The  third  inner 
fold  expands  in  the  posterior  lobe  of  the  tooth  hke  the 
first,  and  two  short  folds  partially  detach  a  small  ac- 
cessory lobe  at  the  posterior  part  of  the  crown.  All 
the  valleys,  fissures,  or  folds,  in  both  the  upper  and  the 
lower  grinders,  are  lined  by  enamel,  which  also  coats 
the  whole  exterior  surface  of  the  crown. 

"  The  character  by  wdiich  horses'  grinders  may  best 
be  distinguished  from  the  teeth  of  other  herbivora  cor- 
responding with  them  in  size,  is  the  great  length  of 
the  tooth  before  it  divides  into  roots.  This  division, 
indeed,  does  not  begin  to  take  place  until  much  of 
the  crown  has  been  worn  away.  Thus,  except  in. old 
horses,  a  considerable  proportion  of  the  whole  of  the 
tooth  is  implanted  in  the  socket  by  an  undivided  base. 
This  is  slightly  curved  in  the  upper  grinders. 

"The  deciduous  molars  have  shorter  bodies  than  the 
permanent,  and  sooner  begin  to  develop  roots.  They 
may  be  distinguished  from  the  rooted  molar  of  a  rumi- 
nant, as  may  also  their  permanent  successors  with 
roots,  by  their  form  and  the  pattern  of  their  grinding 
surface.  The  latter  may  be  a  little  changed  by  the 
partial  obliteration  of  its  enamel  folds,  but  it  gen- 
erally retains  enough  of  its  character  to  show  the 
distinction." 

*  "  The  species  of  paleotlierium,  which  appear  to  have  accom- 
panied the  anoplotheres  in  the  first  introduction  of  hoofed  quad- 
rupeds upon  this  planet,  were  characterized  by  the  same  com- 
plete dental  formula,  namely,  forty-four  functionally  developed 
teeth." — Owen. 


ARISTOTLE'S   MISTAKE.  69 

Monsieur  Lecoq's  description  of  the  grinder  teeth, 
like  the  one  just  quoted,  is  a  contribution  to  dental 
science.  The  repetition  of  facts  already  given  is  off- 
set by  its  additional  facts,  and  its  historical  informa- 
tion is  as  interesting  as  are  Prof.  Owen's  comparisons. 
It  is  as  follows  ("Traite  de  I'Exterieur  du  Cheval  et  des 
Priucipaux  Animaux  Domestiques") : 

"  It  was  l)elieved  for  a  long  time  that  the  grinders  of 
Solipeds  were  all  persistent  teeth.  This  error,  founded 
on  the  authority  of  Aristotle,  was  so  deeply  rooted  that, 
although  Euini,  toward  the  end  of  the  Sixteenth  cen- 
tury, had  discovered  the  existence  of  two  temporary 
molars,  Bourgelat  did  not  believe  it  when  he  founded 
the  French  veterinary  schools,  and  was  only  convinced 
when  Tenon  proved  by  specimens,  in  1770,  that  the 
first  three  are  deciduous. 

''  Generally  considered,  the  grinder  arcades  have  not 
the  same  disposition  in  both  jaws.  Wider  apart  in  the 
superior  one,  they  form  a  slight  curve,  whose  convexity 
is  outward.  In  the  inferior  jaw,  on  the  contrary,  the 
two  arcades  separate  in  the  form  of  a  V  toward  the  back 
of  the  moutii.  Instead  of  coming  in  contact  by  level 
surfoces,  the  grinders  meet  by  inclined-planes.  In  the 
lower  jaw  the  internal  border  is  higher  than  the  exter- 
nal, while  the  reverse  is  the  rule  in  the  upper.  This 
circumstance  prevents  the  lateral  movement  of  the 
lower  jaw  taking  place  without  separation  of  the  inci- 
sors, and  thus  saves  them  from  friction. 

"  Like  the  incisors,  each  grinder  presents  for  study 
a  free  and  a  fixed  portion.  The  free  portion  (the  body), 
nearly  square  in  the  upper  grinders,  broader  than 
thick  in  the  lower,  shows  at  the  external  surface  of  the 
former  two  longitudinal  grooves,  the  anterior  of  which 


70  THE  PEPtMAIS^ENT  DE:N^TITI0X. 

is  the  deeper,  both  bemg  continued,  on  the  incased 
portion.  This  is  not  the  case  with  the  lower  grinders, 
which  have  hut  one  narrow  and  frec[uently  indistinct 
groove.  The  internal  surface,  in  both  jaws,  presents 
only  one  groove,  and  that  but  little  marked.  It  is 
placed  backward  in  the  upper  teeth,  and  is  most  ap- 
l^arent  toward  the  root.  The  anterior  and  posterior 
faces  of  the  respective  teeth,  which  are  in  contact  with 
each  other,  are  nearly  level,  but  at  the  extremities  of 
the  arcades  the  isolated  faces  are  converted  into  a  nar- 
row border. 

"  The  grinders  are  separated  from  each  other  by  their 
imbedded  portion,  particularly  at  the  extremities  of 
tiie  arcades,  an  arrangement  which  strengthens  them 
by  throwing  the  strdin  put  upon  the  terminal  teeth 
toward  the  middle  of  the  line.  They  exhibit  a  variety 
of  roots.  In  the  first  and  last,  either  above  or  below, 
there  are  three,  while  the  intermediate  teeth  have  four 
in  the  upper  jaw,  and  only  two  in  the  lower.  The 
root,  if  examined  a  short  time  after  the  eruption  of 
the  free  portion,  looks  only  like  the  shaft  of  the  latter, 
without  fangs,*  but  a  wide  internal  cavity.  The. roots 
form  when  the  teeth  begin  to  be  pushed  from  their 
sockets  ;  they  cease  to  grow  as  soon  as  their  cavities 
are  filled  vv^ith  new  dentine,  but  the  tooth,  constantly 
growing,  causes  the  walls  inclosing  it  to  contract,;  so 
that  in  extreme  age  the  shaft,  completely  w^orn  away, 
leaves  several  stumps  formed  by  tlie  roots. 

"  The  replcicement  of  the  twelve  molars  is  not  at  all 
like  what  happens  with  the  incisors.     They  grow  im- 

*  Fang-  for  root  is  obsolete.  Fang  signifies  cro?r«— especially 
the  pointed  teeth  of  animals  of  prey  and  the  poison-fang  of  ser- 
pents.    Fang  for  both  root  and  crown  causes  confusion. 


EELATEVE  SIZE  OF  THE  Gr.INDEES.  71 

mediately  below  the  temporary  teeth,  and  divide  their 
two  roots  into  four,  the  absorbing  process  continuing 
until  the  bodies  are  reduced  to  simple  plates  and  fall 
off." 

In  measuring  the  teeth  in  a  large-sized  head  the 
following  facts  and  figures  were  elicited :  Length  of 
grinder  rows,  7  inches.  Space  between  the  sixth 
grinders,  upper  rows,  measuring  from  the  inner  sur- 
faces, but  not  inchiding  the  angles,  3  inches ;  center  of 
rows,  2ff ;  first  gi'inders,  not  including  the  space  of 
the  angles,  2^.  Lower  rows:  Between  the  sixth 
gi-inders,  2|;  center  of  row^s,  lf|;  first  grinders,  IJ. 
Upper  tush  from  first  grinder,  2-J ;  from  third  incisor, 
1|.  Lower  tush  from  grinder,  3-|;  from  incisor,  |. 
Space  between  the  upper  tushes,  2 ;  between  the  lower. 
If.  Space  betw^een  the  upper  corner  incisors,  measur- 
ing from  center  of  teeth,  2;  lower,  l^f ;  between  the 
upper  diWders,  H;  lower.  If.  Distance  around  semi- 
circle of  upper  incisors,  4y\ ;  around  lower,  3^. 

As  a  supplement  to  the  above,  the  following  extract 
is  made  from  "'  An  Essay  on  the  Teeth "  by  Surgeon 
John  Hughes  ("Veterinarian/'  1841,  "Proceedings 
Vet.  Med.  Ass.,"  p.  22): 

"  The  iipper  and  lower  grinders  will  measure  from 
2-|-  to  3  inches  in  length.  In  transverse  diameter  the 
former  exceed  the  latter  in  the  proportion  of  ?  to  4. 
The  aggregate  measurement  of  the  sockets  of  the  up- 
per grinders  is  about  7  inches.  The  first  tooth  occu- 
pies one  inch  and  a  half  of  this  space,  the  second  1|-, 
the  third  1^,  the  fourth  1,  the  fifth  1,  and  the  sixth  1^. 
The  breadtii  of  the  con-esponding  lower  teeth  is  about 
the  same  as  that  of  the  upper." 


73  THE  PERMAXEXT  DENTITION. 

There  is  a  difterence  in  the  structure  of  all  the  teeth, 
and  an  expert  can  tell  to  which  socket  each  belongs. 
They  tit  their  sockets  accurately,*  are  braced  all  round 
by  the  jawbone  processes,  and  receive  besides  support 
and  protection  from  the  gums,  which  adhere  to  them 
tenaciously  and  are  almost  as  hard  as  cartilage.  Use 
and  time,  however,  work  changes,  the  teeth  all  wearing 
down,  the  incisors  in  particular  clianging  shape  and 
projecting  outward.  At  the  age  of  twelve  years  the 
gums  begin  to  slacken,  causing  the  teeth  to  look 
longer.  The  change  from  the  upriglit  position  of  the 
incisors,  and  the  increased  space  between  them  and 
the  canines,  is  caused  by  the  elongation  of  the  jaws, 
wiiich  carries  the  incisors  outward.  Tlie  canines  do 
not  change  their  position,  but  they  become  mere  stubs. 

*  "  The  manner  of  attachment  of  the  human  teeth  is  that 
termed  'gomphosis,'  ^.  e.,  an  attachment  comparable  to  the  fit- 
ting of  a  peg  into  a  hole.  The  bony  sockets,  however,  allow  of 
a  considerable  degree  of  motion,  as  may  be  seen  by  examining 
the  teeth  in  a  dried  skull,  the  fitting  being  in  the  fresh  state 
comi)leted  by  the  interposition  of  the  dense  periosteum  of  the 
socket.  This  latter,  by  its  elasticity,  allows  of  a  small  degree 
of  motion  in  the  tooth,  and  so  doubtless  diminishes  the  shock 
which  would  be  occasioned  by  mastication  were  the  teeth  per- 
fectly immovable  and  without  a  yielding  lining  within  their 
sockets." — C.  S,  Tomes,  "Dental  Anatomy"  <f-c  ,  p.  23, 

John  Hunter  says  ("  Human  Teeth  ") :  "  The  roots  of  the 
teeth  are  fixed  in  the  gum  and  alveolar  processes  by  that  species 
of  arriculation  called  (/omphosis,  which  in  some  measure  resem- 
bles a  nail  driven  into  a  ynece  of  wood.  They  are  not,  however, 
firmly  united  with  the  processes,  f<ir  every  tooth  has  s  me  de- 
gree of  motion;  and  in  heads  which  have  been  boiled  cr  macer- 
ated in  water,  so  as  to  destroy  the  periosteum  and  adhesion  of 
the  teeth,  we  find  them  so  loosely  connected  with  their  sockets 
that  the  incisors  are  ready  to  drop  out,  tlie  grinders  remaining, 
&s  it  were,  hooked,  from  the  number  and  shape  of  their  roots. " 


THE   IIOKSE  AS   A  MILLER.  73 

Notwithstanding  all  these  changes  it  is  a  rare  thing  to 
see  a  missing  incisor  or  grinder.  The  canines,  how- 
ever, owing  perhaps  to  their  sharp  points,  not  only 
wear  out,  but  now  and  then,  in  extreme  old  age,  fall 
out. 

The  permanent  teeth  agree  with  the  temporary  in 
but  few  respects,  though  the  general  appearance  of  the 
respective  teeth  is  nearly  the  same.  They  differ  in 
many  respects.  Their  bodies  are  larger  and  denser, 
and  their  roots  longer  and  stronger.  The  grooving  of 
the  incisors  is  the  reverse;  the  outer  surface  is  usually 
double  grooved,  the  inner  smooth,  both  being  slightly 
rounded.  They  are  less  upright  in  position,  and  less 
sharp,  but  are  more  discolored,  and  tlie  "marks"  (in- 
fundibula)  are  wider  and  deeper  and  wear  out  more 
slowly.  They  attain  their  grow^th  more  slowly,  and  a 
healthy  tooth  continues  to  grow  throughout  life. 

In  proof  of  the  last  assertion  many  authorities  could 
be  cited,  but  those  that  follow  must  suffice.  It  is  a 
wise  provision  of  Nature,  as  but  for  it  a  horse's  teeth, 
particularly  the  grinders,  would  be  worn  to  stubs  in 
two  or  three  years  after  their  development.  Prof. 
M.  H.  Bouley  and  Surgeon  P.  B.  Ferguson  say  ("  Vet- 
erinarian," 1844) : 

"The  growth  throughout  life  is  a  compensation  for 
tlie  enormous  wear  of  the  teeth,  the  horse  having  to 
perform  for  himself  that  which  the  miller  performs  for 
man;  and  thus  during  a^^erylong  time  the  teeth  pre- 
serve, if  not^  their  form,  at  least  their  length." 

Prof.  A.  Chauveau,  referring  to  the  horse,  says: 

"  The  permanent  teeth  present  in  their  development 
a  common  but  very  remarkable  characteristic,  rarely 
4 


74  THE    PERMAXEXT   DEXTITIOX. 

met  with  in  other  animals.  They  are  thrust  up  from 
the  alveoli  during  the  entire  life  of  the  animal  to  re- 
place the  surface  v>'orn  by  friction." 

The  activity  of  the  growth  of  the  grinders  is  re- 
markable about  the  seventh  year,  for  at  this  time 
their  roots  begin  to  develop ;  growth  is  thus  going  on 
at  both  ends  at  the  same  time.  A 
third  movement  is  now  at  least 
apparent,  for  the  undivided  base 
in  the  socket  appears  to  be  slowly 
pushed  out,  which  may  partly  ac- 
count for  the  shrinkage  of  the 
gums.  The  tenacity  of  the  adhe-  Left  uppeTTnoiar. 
sion  of  the  periosteum  would  not  wholly  prevent  this 
movement,  for  it  acts  as  a  cushion,  its  elasticity  pre- 
venting concussions.  The  undivided  base  resembles 
a  post  set  in  the  ground,  except  that  the  implanted 
part  is  smaller  than  the  crown. 

Up  to  about  the  sixteenth  year,  the  grow^tli  of  the 
teeth  results  chiefly  from  vitality  transmitted  through 
the  medium  of  the  pulp.  After  the  pulp  has  become 
converted  into  dentine,  however,  the  tooth  "  draws  its 
nourishment  from  the  blood-vessels  of  the  socket."* 

Surgeon  Louis  Brandt  ("  The  Age  of  Horses,"  In- 
dianola,  Texas,  1860)  says  of  the  incisors  r 

**  The  length  of  the  teeth  is  constantly  decreasing, 
and  often  quite  regularly,  so  that  in  extreme  old  age 
they  will  sometimes  not  exceed  half  an  inch  in  length, 
while  at  their  prime  they  were  2^  to  3  inches  long. 
Their  breadth  decreases  nearly  in  proportion  to  the 
decrease  in  length." 

*  See  pages  169-70. 


CHAPTER    IV. 

THE   CAITIXE   TEETH   OR  TUSHES. 

Practically  Useless. — Different  in  their  Nature  from  the  other 
Teeth. — Were  they  formerly  Weapons  of  Offense  and  De- 
fense?— Views  of  Messrs.  Darwin,  Hunter,  Bell,  Youatt,  and 
Winter. — Their  time  of  Cutting  the  most  Critical  Period  of 
the  Horse's  Life. 

The  Canine  Teeth  {laniarii  denies),  comparatively 
speaking,  are  of  little  practical  use ;  at  least  they  are 
of  little  use  to  the  modern  iiorse.  They  have  been 
much  reduced  in  size  during  the  evohition  of  the  horse, 
and,  if  Mr.  C.  R.  Darwin's  theory  is  correct,  are  prob- 
ably ''in  tlie  course  of  ultimate  extinction."  They 
distinguish  the  sex,  it  is  true,  but  their  loss  would  not 
be  felt  on  that  account.  The  horse  sometimes  uses 
them  in  tearing  bark  from  trees,  for  he  is  by  instinct 
his  own  (botanical)  doctor,  and  the  bark  is  his  medi- 
cine. The  sharp  points  of  the  tushes  penetrate  the 
bark  more  readily  than  the  incisors,  and  apparently 
the  horse  wishes  to  save  his  incisors,  thus  showing  his 
horse-sense.  Their  nature  is  different  from  that  of 
the  other  teeth,  for  the  incisors  and  grinders  grow  till 
old  age.  This  is  not  the  case  with  the  tushes,  and, 
further,  they  are  never  in  apposition  (superposed),  and 
consequently  do  not  wear  one  another. 

The  lower  tushes,  as  before  said,  are  about  three- 
fourths  of  an  inch  from  the  corner  incisors,  and  about 
three  inches  and  a  half  from  the  first  grinders.     The 


76  THE  CAXIiq-E  TEETH. 

space  between  fclie  upper  tuslies  and  the  corner  incisors 
is  doable  that  of  the  lower,  and  they  are  consequently 
three-fourths  of  an  inch  nearer  the  grinders.  The  dis- 
tances may  vary  a  half  an  inch  or  more.  The  space 
between  the  tushes  and  grinders  is,  as  already  said, 
called  the  diastema. 

The  average  bight  of  the  tushes  when  full  grown  is 
about  three-fourths  of  an  inch.  They  resemble  tri- 
angles, having  broad  bases  and  sharp  crowns,  the  latter 
being  remarkable,  says  Prof  Owen,  "for  the  folding  in 
of  the  anterior  and  posterior  margins  of  enamel,  which 
here  includes  an  extremely  thin  layer  of  dentine." 
They  have  a  slight  outward  inclination,  that  of  the 
lower  teeth  exceeding  that  of  the  upper.  Their  outer 
surface  is  oval,  the  inner  (in  the  young  horse)  being 
deeply  grooved.  As  age  advances  the  inner  snrfiice 
becomes  oval  also,  and  the  crowns  more  or  less  blunt. 
The  root  of  a  tnsh,  which  is  longer  than  its  body, 
has  a  distinct  backward  curvature,  rendering  the  ex- 
traction of  these  teeth  almost  impossible.  The  tushes 
have  no  "marks"  (infundibula),  the  nerve  cavity  ex- 
tending through  nearly  the  entire  length  of  the  tooth. 

Monsieur  Lecoq  says : 

"The  free  portion  of  the  tusk,  slightly  curved  and 
thrown  outward,  particularly  in  the  lower  jaw,_presents 
two  faces  (internal  and  external),  separated  from  one 
another  by  two  sharp  borders,  which  incline  to  the 
inner  side,  and  meet  in  a  point  at  the  extremity  of  the 
tooth.  The  external  face,  slightly  rounded,  presents  a 
series  of  fine  strife,  longitudinal  and  parallel.  The 
internal  has  a  conical  eminence  in  its  middle,  whose 
point  is  directed  toward  that  of  the  tooth,  and  is  sep- 
arated from  each  border  by  a  deep  groove. 


SIMPLICITY  OF  THEIR  STRUCTURE.  77 

"The  root  of  the  tusk,  more  curved  than  the  free 
portion,  bears  internally  a  cavity  analogous  to  that  of 
the  root  of  the  incisors,  and,  like  it,  diminishes  in  size 
and  finally  disappears  as  age  advances ;  but  it  is  always 
relatively  larger,  because  of  the  absence  of  the  infun- 
dibulum  in  the  canine  teeth. 

"  The  structure  of  these  teeth  is  much  simpler  than 
that  of  the  incisors,  consisting,  as  they  do,  of  a  central 
mass  of  dentine,  hollowed  by  the  pulp  cavity,  and  cov- 
ered by  an  external  layer  of  enamel,  on  which  is  de- 
posited a  little  cement." 

As  there  is  more  or  less  mystery  about  the  tushes, 
and  as  they  are  important  factors  in  the  consideration 
of  the  problem  of  the  evolution  of  the  horse  as  well  as 
other  animals,  a  few  extracts  from  the  works  of  well- 
known  scientific  men,  giving  their  views  on  the  sub- 
ject, will  prove  interesting  if  not  instructive. 

Mr.  Charles  R  Darwin  gives  the  following  interest- 
ing account  of  tushes  and  their  uses  in  certain  animals, 
among  them  the  horse  ("  Descent  of  Man,"  vol.  ii,  pp. 
245-G-7) : 

"  Male  quadrupeds  which  are  furnished  with  tusks 
use  tliem  in  various  ways,  as  in  the  case  of  horns. 
The  boar  strikes  laterally  and  upward,  the  musk-deer 
with  serious  effect  downward.  The  walrus,  though 
having  a  short  neck  and  unwieldy  body,  ^can  strike 
upward,  downward,  or  sideways  with  equal  dexterity.' 
The  Indian  elephant  fights,  as  I  was  informed  by  the 
late  Dr.  Falconer,  in  a  difi'erent  manner  according  to 
the  position  and  curvature  of  his  tusks.  When  they 
are  directed  forward  and  upward,  he  is  able  to  fling  a 
tio-er  to  a  p-reat  distance — it  is  said  to  even  thirty  feet; 


78  THE  CANINE  TEETH. 

wlien  they  are  short  and  turned  downward,  he  en- 
deavors suddenly  to  pin  the  tiger  to  the  ground,  and 
in  consequence  is  dangerous  to  the  rider,  who  is  liable 
to  be  dismounted. 

^•' Very  few  male  quadrupeds  possess  weapons  of  two 
distinct  kinds  specially  adapted  for  fighting  with  rival 
males.  The  male  muntjac-deer  {Cer cuius),  however, 
offers  an  exception,  as  he  is  provided  with  horns  and 
exserted  canine  teeth.  But  one  form  of  weapon  has 
often  been  replaced  in  the  course  of  ages  by  another 
form,  as  we  may  infer  from  wliat  follows.  With  rumi- 
nants the  development  of  horns  generally  stands  in  an 
inverse  relation  with  that  of  even  moderately  well- 
developed  canine  teeth.  Thus  camels,  guanacoes, 
chevro tains,  and  musk-deer  are  hornless,  and  they 
have  efficient  canines,  these  teeth  being  'always  of 
smaller  size  in  the  females  than  in  the  males.'  Male 
deer  and  antelopes,  on  the  other  hand,  possess  horns, 
and  they  rarely  have  canine  teeth,  and  these  when 
present  are  always  of  smaller  size,  so  that  it  is  doubt- 
ful whether  they  are  of  any  service  in  their  battles. 
With  Antelope  wontana  they  exist  only  as  rudiments 
in  the  young  male,  disappearing  as  he  grows  old. 
Stallions  have  small  canine  teeth,  but  they  do  not 
appear  to  be  used  in  fighting,  for  stallions  bite  with 
their  incisors,  and  do  not  open  their  mouths  widely 
like  camels  and  guanacoes.  Whenever  the  adult  male 
possesses  canines  now  in  an  inefficient  state,  while  the 
female  has  either  none  or  mere  rudiments,  we  may 
conclude  that  the  early  male  progenitor  of  the  species 
was  provided  with  efficient  canines,  which  had  been 
partially  transferred  to  the  females.  The  reduction  of 
these  teeth  in  the  males  seems  to  have  followed  from 
some  change  in  their  manner  of  fighting,  often  caused 


TUSHES  TEX  FEET  LON^G.  79 

(but  not  in  the  case  of  the  horse)  by  the  development 
of  new  weapons." 

In  the  first  voUime  of  the  "Descent  of  Man,"  page 
139,  Mr.  Darwin  attributes  the  reduction  in  size  of  the 
tushes  in  horses  to  their  "  habit  of  fighting  with  their 
incisor  teeth  and  hoofs,"  and  on  page  231,  of  the  sec- 
ond vohinie,  he  continues  the  discussion  of  canines  in 
different  animals  as  follows: 

"  In  the  male  dugong  the  upper  incisors  form  offen- 
sive weapons.  In  the  male  narwhal  one  of  the  upper 
teeth  is  developed  into  the  well-known,  spirally-twisted, 
so-called  horn,  which  is  sometimes  from  nine  to  ten 
feet  long.  It  is  beheved  that  the  males  use  these  horns 
for  fighting  together,  for  'an  unbroken  one  can  hardly 
be  got,  and  occasionally  one  may  be  found  with  the 
point  of  another  jammed  into  the  broken  place.'  The 
tooth  on  the  opposite  side  of  the  head  in  the  male  con- 
sists of  a  rudiment  about  ten  inches  in  length,  which 
is  imbedded  in  the  jaw.  It  is  not,  however,  very  un- 
common to  find  double-horned  male  narwhals  in  which 
both  teeth  are  well  developed.  In  the  females  both 
teeth  are  rudimentary.      The  male  cach'alot*  has  a 

*  "  Sperm-wliale  or  cachalot  {Physeter  macrocephahis).  My 
friend  Mr.  Broderip  possesses  a  tooth  of  a  male  Physeter,  with 
the  base  open  and  uncontracted,  which  measures  nine  inches 
and  a  half  in  length,  nine  inches  in  circumference,  and  weighs 
three  pounds.  An  ingenious  whale-fisher  has  carved  the  chief 
incidents  of  his  exciting  and  dangerous  occupation  on  one  side 
of  this  very  fine  tooth.  Tlie  other  side  bears  the  following  in- 
scription :  '  The  tooth  of  a  sperm-whale,  that  was  caught  by  the 
ship  Adam's  crew,  off  Albemarle  Point,  and  made  100  bbls.  of  oil, 
in  the  year  1817.'  Below  the  inscription  are  two  excellent 
figures  of  the  cachalot,  one  spouting,  the  other  dead  and  marked 
for  flensing."— Oicen's  ''Odontography"  Vol.  I,  pp  353-4. 


80  THE   CAJ^IXE  TEETH. 

larger  head  than  the  female,  and  it  no  doubt  aids  these 
animals  in  their  aquatic  battles.  Lastly,  the  adult 
male  ornithorhyn'chus  is  provided  with  a  remarkable 
apparatus,  namely,  a  spur  on  the  foreleg,  closely  re- 
sembling the  poison  fang  of  a  venomous  snake.  Its 
use  is  not  known,  but  we  may  suspect  it  serves  as  a 
Aveapon  of  otfense.  It  is  represented  by  a  mere  rudi- 
ment in  the  female."  * 

The  foregoing  extracts  would  not  be  complete  with- 
out giving  the  views  of  this  great  disciple  of  evolution 
concerning  the  same  teeth  in  man.  He  says  ("  Descent 
of  Man,"  vol.  i,  p.  198) : 

"  "W^e  have  thus  far  endeavored  rudely  to  trace  the 
genealogy  of  the  vertebrata  by  the  aid  of  their  mutual 
affinities.  We  will  now  look  to  man  as  he  exists,  and 
we  shall,  I  think,  be  able  partially  to  restore  during 
successive  periods,  but  not  in  due  order  of  time,  the 
structure  of  our  early  progenitors.  This  can  be  effected 
by  means  of  the  rudiments  which  man  still  retains,  by 
the  characters  which  occasionally  make  their  appear- 
ance in  him  through  reversion,!  and  by  tlie  aid  of  the 
principles  of  morphology  and  embryology.];     The  early 

*  For  further  information  concerning  this  strange  animal  see 
the  "  Vocabulary." 

f  "  The  occasional  appearance  at  the  present  day  of  canine 
teeth  which  project  above  the  others,  with  traces  of  a  diastema 
or  open  space  for  the  reception  of  the  opposite  canines,  is  in  all 
probability  a  case  of  reversion  to  a  former  state,  when  the  pro- 
genitors of  man  were  provided  with  these  wea.'pons."—"" Descent 
of  Mm,"  Vol.  II,  p.  309. 

X  "  The  human  em'bryo  re&emldes  in  various  points  of  struc- 
ture certain  low  forms  when  adult.  For  instance,  the  heart  at 
first  exists  as  a  simple  pulsotin?:  vessel ;  tlie  excreta  are  voided 
through  a  cloacal  i  as?ng;^  and  the  os  coccyx  projects  like  a  true 


THE  EARLY   PROGr>:TTOrvS   OF  ^lAl^.  81 

progenitors  of  man  were  no  doubt  once  covered  with 
hair,  both  sexes  having  beards.  Their  ears  were 
pointed  and  capable  of  movement,  and  their  bodies 
were  provided  with  a  tail,  having  the  j^ roper  muscles. 
Their  liQibs  and  bodies  were  also  acted  on  by  muscles 
which  now  only  occasionally  reappear,  but  are  normally 
present  in  the  quadrumana.     The  great  artery  and 


tail,  'extending  considerably  beyond  the  rudimentary  legs.' 
The  great-toe,  as  Prof.  Owen  remarks,  '  which  forms  tlie  ful- 
crum when  standing  or  walking,  is  perhaps  the  most  character- 
istic peculiarity  in  the  human  structure ;'  but  in  an  embryo 
about  an  inch  in  length,  Prof.  VVyman  found  that  the  great-toe 
was  shorter  than  the  others,  and  instead  of  being  parallel  to 
them,  '  projected  at  an  angle  from  the  side  of  the  foot,  thus  cor- 
responding with  the  permanent  condition  of  this  part  in  the 
quadrumana.'  *  *  *  When  the  extremities  are  developed, 
'  the  feet  of  lizards  and  mammals,  the  wings  and  feet  of  birds, 
no  less  than  the  hands  and  feet  of  man,  all  arise  from  the  same 
fundamental  form.'    (Von  Baer)."— ''Descent  of  Man,"  Vol.  I,  pp. 

"  Each  human  individual  is  developed  from  an  egg,  and  this 
egg  is  a  simple  cell,  like  that  of  any  animal  or  plant.  The  em- 
bryo, in  the  early  stages  of  development,  is  not  at  all  different 
from  those  of  other  animals.  At  a  certain  period  it  has  essen- 
tially  the  anatomical  structure  of  a  lancelet  (the  lowest  verte- 
brate), later  of  a  fish,  and  in  subsequent  stages  those  of  am- 
pliibian  and  mammal  forms.  In  the  further  evolution  of  these 
mammal  forms,  those  first  appear  which  stand  lowest  in  the 
series,  namely,  forms  allied  to  beaked  animals  (ornithorhyn- 
chus) ;  then  those  allied  to  pouched  animals  (marsupials),  which 
are  followed  by  forms  most  resembling  apes,  till  at  last  the 
peculiar  human  form  is  produced  as  the  final  result.  Every  one 
knows  that  the  butterfly  proceeds  from  a  pupa,  the  pui)a  from  a 
caterpillar,  to  which  it  bears  no  resemblance,  and  again  the  cat- 
erpillar from  the  e^,g  of  the  butterfly.  But  few,  except  those  of 
the  medical  profession,  are  aware  that  man,  in  the  course  of  his 
individual  evolution,  passes  through  a  series  of  transformations 


82  THE  CAXIXE  TEETH. 

nerve  of  the  humerus  ran  through  a  supra-condyloid 
fora'men.  At  this  or  some  earlier  period  the  intestine 
gave  forth  a  much  larger  diverticulum  or  caecum  than 
that  now  existing.  The  foot,  judging  from  the  con- 
dition of  the  great-toe  in  the  fetus,  was  then  prehen- 
sile, and  our  early  progenitors  were  no  doubt  arboreal 
in  their  habits,  frequenting  some  warm,  forest-clad 
land.  The  males  were  provided  with  great  canine 
teeth,  which  served  them  as  formidable  weapons."* 

no  less  astonishing  and  remarkable  than  the  well  known  meta- 
morphoses of  the  butterfly.  *  *  *  An  examination  of  the 
human  embryo  in  the  third  or  fourth  week  of  its  evolution 
shows  it  to  be  altogether  different  from  the  fully  developed 
man,  and  that  it  exactly  corresponds  to  the  undeveloped  em- 
bryo-form presented  by  tiie  ape,  the  dog,  the  rabbit,  the  horse, 
and  other  mammals,  at  the  same  stage  of  their  ontog'eny  (germ 
history),  which  may  be  demonstrated  by  placing  the  respective 
embr}^os  side  by  side.  At  this  stage  it  is  a  bean-shaped  body  of 
very  simple  structure,  with  a  tail  behind,  and  two  pairs  of  pad- 
dles, resembling  the  fins  of  fish,  and  totally  dissimilar  at  the 
sides  to  the  limbs  of  man  and  other  mammals.  Nearly  the 
whole  of  the  front  half  of  the  body  consists  of  a  shapeless  head, 
without  a  face,  on  the  sides  of  which  are  seen  gill-fissures  and 
gill-arches,  as  in  fishes.  *  *  *  The  human  embryo  passes 
through  a  stage  in  which  it  possesses  no  head,  no  brain,  no 
skull ;  in  which  the  trunk  is  still  entirely  simple  and  undivided 
into  head,  neck,  breast,  and  abdomen,  and  in  which  there  is  no 
trace  of  arms  or  legs." — Ernst  Heinrich  Haeckel,  ''The  Rcolution 
of  Man,"  Vol.  I,  pp.  3,  IS,  253. 

*  Mr.  Darwin  continues:  "  At  a  much  earlier  time  the  uterus 
was  double ;  the  excreta  were  voided  through  a  cloaca,  and  the 
eye  was  protected  by  a  third  eyelid  or  nictitating  membrane. 
At  a  still  earlier  period  the  progenitors  of  man  must  have  been 
aquatic  in  their  habits,  for  mor|>hology  plainly  tells  us  that  our 
lungs  consist  of  a  modified  swim-bladder,  which  once  served  as 
a  float.  The  clefts  on  the  neck  in  the  embryo  of  man  show 
where  the  branchiae  once  existed,"  «Sic.,&c. 


DARWIX   OXLY   CORIIOBOIIATES  IirXTER.  83 

Agaiu,  on  page  138  of  the  same  volume,  Mr.  Darwin 

says : 

^•Tbe  early  progenitors  of  man  were,  as  previously 
stated,  probably  furnished  with  great  canine  teeth ;  but 
as  they  gradually  acquired  the  habit  of  using  stones, 
clubs,  or  other  weapons  for  fighting  with  their  enemies, 
they  would  have  used  their  jaws  and  teeth  less  and 
less.  In  this  case  the  jaws  and  the  teeth  would  have 
become  reduced  in  size,  as  we  may  feel  sure  from  nu- 
merous analogous  cases."* 

Dr.  Jolm  Hunter,  writing  nearly  one  hundred  years 
before  Mr.  Darwin's  time,  says  (''The  Human  Teeth," 
p.  29); 

"  The  use  of  the  cuspidati  would  seem  to  be  to  lay 
hold  of  substances,  perhaps  even  living  animals.  They 
are  not  formed  for  dividing,  as  the  incisors  are,  nor 
are  they  fit  for  grinding.  We  may  trace  in  these  teeth 
a  similarity  in  shape,  situation,  and  use,  from  the  most 
imperfectly  carnivorous  animal — which  we  believe  to 
be  the  human  species — to  the  most  perfectly  carnivo- 
rous, namely,  the  lion." 

The  editor  of  Dr.  Hunter's  work,  Mr.  Thomas  Bell, 
F.RS.,  comments  as  follows  on  the  above  extract: 

"  That  our  conclusions  as  to  the  functions  of  an 
organ  as  it  exists  in  man,  when  drawn  exclusively  from 
analogous  structures  in  the  lower  animals,  will  fre- 

*  "The  jaws,  together  with  their  muscles,  would  then  have 
become  reduced  throutrh  disuse,  as  would  the  teeth,  through  the 
not  well  understood  principles  of  correlation  and  the  economy  of 
growth  ;  for  we  everywhere  see  that  parts  which  are  no  longer 
of  service  are  reduced  in  size." — "jDescent  of  Man.''* 


84  THE  CA^sIXE  TEETH. 

quently  prove  erroneous,  is  strikingly  shown  in  these 
observations  on  the  use  of  the  cuspidatus.  The  simple 
and  obvious  use  of  this  tooth,  in  the  haman  species,  is 
to  tear  such  portions  of  food  as  are  too  hard  or  tough 
to  be  divided  by  the  incisors ;  and  we  frequently  find 
it  far  more  developed  in  animals  which  are  known  to 
be  exclusively  frugivorous.  Not  only  is  its  structure 
wholly  nnadapted  for  such  an  object  as  that  assigned 
to  it  in  the  text,  but  there  is  no  analogous  or  other 
ground  for  supposing  that  man  was  originally  con- 
structed for  the  pursuit  and  capture  of  living  prey. 
His  naturally  erect  position  and  the  structure  of  the 
mouth  would  render  this  impossible  by  the  means  in- 
ferred by  Hunter;  and  the  possession  of  so  perfect  an 
instrument  as  the  hand  obviates  the  necessity  of  his 
ever  employing  any  other  organ  for  the  purpose  of 
seizing  or  holding  food  of  whatever  description." 

Prof.  William  Youatt  says  ("The  Horse,*'  p.  22G): 

"  At  the  age  now  under  consideration  (the  fourth 
year)  the  tushes  are  almost  peculiar  to  the  horse,  and 
castration  does  not  appear  to  prevent  or  retard  their 
development.  All  mares,  however,  have  the  germs  of 
them  in  the  chambers  of  the  jaws,  and  they  appear 
externally  in  the  majority  of  old  mares.  Their  use  is 
not  evident.  Perhaps  in  the  wild  state  of  the  horse 
they  are  weapons  of  offense,  and  he  is  enabled  by 
them  to  more  firmly  seize  and  more  deeply  wound  his 
enemy."  * 

*  Prof.  C.  S.  Tomes  says  :  "  In  the  domestic  races  the  tusks  of 
boars  are  much  smaller  than  in  the  wild  animal,  and  it  is  a  curi- 
ous fact  that  in  domestic  races  which  have  become  wild,  the 
tusks  increase  in  size  at  the  same  time  that  the  bristles  become 
more   pronounced.      Mr.   Darwin   suggests  that   the  renewed 


THEir.  PITTSIOLOGICAL  RELATIO^fS.  85 

Surgeon  J.  H.  Winter,  the  author  of  a  work  entitled 
"  On  the  Horse,"  savs : 

^'  It  is  difficult  to  assign  their  use.  Their  position 
precludes  the  possibility  of  their  being  used  as  weapons 
of  offense  or  defense.  They  may  be  viewed  as  a  link 
of  uniformity  so  commonly  traced  in  the  animated 
world." 

Prof.  William  Percivall  says  that  the  cutting  of  the 
tushes  causes  the  constitution  more  derangement  than 
all  the  other  teeth,  and  Prof.  Youatt  and  other  high 
authorities  entertain  similar  views.  The  present  chap- 
ter, therefore,  is  a  proper  one  in  which  to  discuss  '•'  the 
effects  of  dentition  on  the  system  generally."  The 
discussion  of  the  subject  is  left  to  well-known  men. 
Messrs.  Youatt  and  Percivall  were  many  years  ago  the 
editors  of  "The  Veterinarian,"  but  their  books  are 
probably  the  best  monuments  to  their  memory.  Prof. 
William  Williams  is  the  President  of  the  Edinburgh 
Veterinary  College.  Prof.  Youatt  says  ("  The  Horse," 
p.  230) : 

"  This  is  the  proper  place  to  speak  of  the  effect  of 
dentition  on  the  system  generally.  Horsemen  in  gen- 
eral think  too  lightly  of  it,  and  they  scarcely  dream  of 
the  animal  suffering  to  any  considerable  degree,  or 

growth  of  the  teeth  may  perhaps  be  accounted  for  on  the  prin- 
ciple of  correlation  of  growth,  external  agencies  acting  on  the 
skin,  and  so  indirectly  influencing  the  teeth." 

A  strictly  analogous  result  might  or  might  not  follow  in  the 
case  of  the  horse.  If  so,  the  tushes  would  probably  be  used  as 
weapons  of  offense  and  defense.  It  is  reasonable  to  suppose  that 
they  were  so  used  by  the  early  progenitors  of  the  horse,  whose 
large  tushes  are  described  in  the  succeeding  chapter  by  Prof 
Marsh. 


80  THE  CA^'IXE  TEETH. 

absolute  illness  being  produced.  Yet  he  who  lias  to 
do  with  young  horses  will  occasionally  discover  a  con- 
siderable degree  of  febrile  affection  which  he  can  refer 
to  this  cause  alone.  Fever,  cougli,  catarrhal  and  cuta- 
neous affections,  diseases  of  the  eyes,  diarrhea,  dysen- 
tery, loss  of  appetite,  and  general  derangement  will 
frequently  be  traced  to  irritation  from  teething.  It  is 
a  rule  scarcely  admitting  of  the  slightest  deviation, 
that,  when  young  horses  are  laboring  under  febrile 
affection,  the  mouth  should  be  examined,  and  if  the 
tushes  are  prominent  and  pushing  against  the  gums,  a 
crucial  incision  should  be  made  over  them."* 

Prof.  Percivall  says  (*' Hippopathology,"  vol.  ii,  p. 
225) : 

"There  was  a  time  when  I  treated  the  subject  of 
dentition  so  lightly  as  to  think  that  horses  never  suf- 
fered from  such  a  cause.  Experience,  however,  has 
altered  my  opinion.  I  now  frequently  discover  young 
horses  with  disorders  or  febrile  irritations  the  produc- 
tion of  wi]ich  I  hesitate  not  to  ascribe  to  teething. 
Many  years  ago  I  was  consulted  concerning  a  horse 
which  had  fed  sparingly  for  a  fortnight  and  lost  rap- 
idly in  condition.  His  owner,  a  veterinary  surgeon, 
was  apprehensive  about  his  life.  Another  surgeon  was 
of  opinion  that  the  ^cudding'  arose  from  preternatural 

*Prof.  Youatt's  real  sentiments  are  doubtless  here  expressed, 
but,  unfortunately  for  his  consistency,  on  paj^e  227  of  the  same 
work,  in  spbaking  of  the  derangement  caused  by  teething  in 
children  and  dogs,  he  says :  "  The  horse  appears  to  feel  little 
inconvenience.  The  gums  and  palate  are  occasionally  some- 
what hot  and  swollen,  but  the  slightest  scarification  will  remove 
this."  Perhaps  Prof.  Youatt,  like  Prof.  Percivall,  changed  his 
opinion  late  in  life,  and  neglected  to  remove  the  blemish  from 
J  J  is  book. 


WHAT  CHAKGED   PROF.   PERCIVALL'S  MIXD.        SI 

bluntness  of  the  molar  teeth,  which  were  filed.  It 
was  after  this  that  I  saw  the  horse,  and  I  must  confess 
I  was  at  first  quite  as  much  at  a  loss  to  offer  a  satisfac- 
tory interpretation  of  the  case  as  others  had  been. 
While  meditating,  however,  after  my  inspection  of  the 
horse,  on  the  apparently  extraordinary  nature  of  the 
case,  it  struck  me  that  I  had  not  seen  the  tushes.  I 
went  back  into  the  stable  and  discovered  two  little 
tumors,  red  and  hard,  in  the  situation  of  the  inferior 
tusks,  which,  when  pressed,  gave  the  animal  insuffer- 
able pain.  I  instantly  took  out  my  pocket-knife  and 
made  crucial  incisions  through  them  both,  from  which 
moment  the  horse  recovered  his  appetite,  and  by  de- 
grees his  wonted  condition.  This  case  was  the  turn- 
ing point  in  my  practice,  and  caused  me  to  look  more 
closely  into  dentition. 

"  The  cutting  of  the  tushes,  which  may  be  likened 
to  the  eye-teeth  of  children,  costs  the  constitution 
more  derangement  than  all  the  other  teeth  put  to- 
gether; on  which  account,  no  doubt,  it  is  that  the 
period  from  the  iburth  to  the  fifth  year  proves  so  crit- 
ical to  the  horse.  Any  disease,  palmonary  in  particu- 
lar, setting  in  at  this  period,  is  doubly  dangerous.  In 
fact,  teething  is  one  cause  of  the  fatality  among  young 
horses  at  this  period. 

"  D'Arboval  tells  us  to  observe  how  the  vital  energy 
becomes  augmented  about  the  head,  and  upon  the 
mucous  surfaces  in  particular.  He  says:  ^A  local 
fever  originates  in  the  alveolar  cavities.  The  gums 
become  stretched  from  the  pressure  of  the  teeth  against 
them.  They  dilate,  sometimes  split,  and  are  red,  hot, 
and  painful.  The  roots  compress  the  dental  nerves 
and  irritate  the  periosteal  linings  of  the  alveolar  cavi- 
ties.    These  causes  will  enable  us  to  explain  many 


88  THE  CANIXE  TEETH. 

morbid  phenomena  in  horses  about  this,  the  most  crit- 
ical period  of  their  lives.' 

"Wiien  young  horses  are  brought  to  me  now  for 
treatment,"  continues  Prof.  Percivall,  "1  invariably 
examine  the  teeth.  Should  the  tusks  be  pushing 
against  the  gums,  I  let  them  through  by  incisions 
over  their  summits,  and  1  extract  any  of  the  temj)o- 
rary  teeth  that  ap})ear  to  be  obstructing  the  growth  of 
the  permanent.  In  this  way  I  feel  assured  I  have  seen 
catarrhal  and  bronchial  inflammations  abated,  coughs 
relieved,  lymphatic  and  other  glandular  tumors  about 
the  head  reduced,  cutaneous  eruptions  got  rid  of,  de- 
ranged bowels  and  urinary  organs  restored,  api^etite 
returned,  and  lost  condition  riepaired. 

"  I  am  quite  sure  too  little  attention  lias  been  paid 
to  the  teeth  in  the  treatment  of  young  horses,  and  I 
would  counsel  those  who  have  such  charges  by  no 
means  to  disregard  this  remark,  trifling  as  it  may 
appear.  The  pathognomonic  symptoms  calling  our 
attention,  whether  in  young  or  old  horses,  if  not  to 
the  teeth  themselves,  to  the  moutli  in  general,  are 
large  discharges  of  saliva  from  the  mouth,  with  occa- 
sional slobbering;  cudding  of  the  food;  difficulty  of 
mastication  or  deglutition,  or  both,  and  stench  of  buc- 
cal secretion,  perhaps  of  the  breath  as  well." 

Prof.  Percivall  continues  the  discussion  of  the  sub- 
ject of  dentition  and  its  effect  on  the  health  of  the 
horse,  dwelling  more  particularly  on  the  disorder 
known  as  lampa.'^.     He  says: 

^^  There  is  connected  with  dentition  another  pecu- 
liarity in  the  horse  which  we  must  not  allow  to  pass 
unnoticed.    Although  the  period  of  teething,  properly 


LAMPAS  CAUSED   BY  TEETHIN'G.  89 

speaking,  may  be  said  to  terminate  at  the  fiffh  year, 
yet  we  must  recollect  it  iias  been  satisfactorily  demon- 
strated that  there  is  a  process  of  growth  going  on  in 
the  teeth  thronghout  the  remainder  of  life ;  so  that,  in 
fact,  at  DO  period  may  the  animal  be  said  to  be  free 
from  the  influence  of  dentition.  This  accounts  for 
lampas  occurring  in  old  as  Tvell  as  young  hoi^eSj,  and 
furnishes  my  mind  with  strong  proof  that  the  tumidity 
of  the  bars  of  the  mouth  is  dependent  on  operations 
going  on  in  the  teeth,  and  on  that  cause  alone. 

"  What  we  nowadays  understand  by  larapas  is  an 
unnatural  prominence  or  tumidity  of  the  cartilaginous 
bars  forming  the  roof  of  the  mouth.  Naturally,  tlie 
i)ars  are  pale-colored,  whereas  in  a  mouth  aiiected  with 
lampas  they  become  red  and  tumid,  losing  their  cir- 
cumflecture,  and  swelling  to  a  level  with  the  crowns  of 
the  incisor  teeth,  and  in  some  cases  even  beyond  them. 
This  apparent  augmentation  of  substance  is  ascribable 
to  congestion  of  blood-vessels,  but  not  to  that  alone. 
I  believe  that  in  many  cases  there  will,  be  found  to  be 
some  serous  and  albuminous  infiltration  into  the  cel- 
lular membrane  attaching  the  bars  to  the  hard  palate, 
and  that  this  will  account  for  the  length  of  time  the 
swelling  sometimes  continues,  as  well  as  for  the  little 
relief,  in  regard  to  their  diminution,  which  in  such 
cases  attends  lancing  of  the  gums. 

"  Although  in  young  horses  it  is,  I  believe,  admitted 
that  lami:>as  is  caused  by  the  cutting  of  the  teeth,  yet 
in  old  horses  th^re  are  those  who  ascribe  its  produc- 
tion to  other  causes,  and  imagine  it  has  a  great  deal  to 
do  with  a  horse's  health,  or  rather  with  his  feeding. 
That  lampas  may  in  some  eases  be  the  cause  of  tender- 
ness in  mastication,  I  do  not  deny;  but,  at  the  same 
time,  I  think  I  may  safely  affirm  that  in  nine  cases  out 


90  THE  CANINE  TEETH. 

of  ten  the  cause  of  loss  of  appetite  will  be  found  else- 
where. The  reason  why  lampas  appears  in  aged  horses 
is,  in  my  opinion,  as  before  stated,  on  account  of  the 
continuance  of  the  process  of  growth  in  the  teeth 
throughout  hfe,  with  the  nature  and  laws  of  which  we 
are,  in  our  present  state  of  knowledge,  too  little  ac- 
quainted to  pretend  to  say  why  it  should  exist  in  one 
horse  and  not  in  another,  or  why  it  should  only  at 
times  appear  in  the  same  horse. 

"Is  lampas  a  disease?  The  complaints  which  daily 
reach  our  ears  persuade  us  it  is.  Every  groom  having 
an  unthriving  horse,  or  one  that  does  not  feed,  is  sure 
to  search  for  lampas.  If  he  finds  it,  in  his  mind  the 
cause  of  lack  of  thrift  is  detected,  and  the  remedy 
obvious — burning.  Many  a  horse  has  been  subjected 
to  this  torturing  operation,  and  has  thereby  got  added 
to  his  other  ailments  a  foul,  sloughy,  carious  sore  on 
the  roof  of  his  mouth. 

"Supposing  that  lampas  be  owing  to  the  teeth,  do 
not  the  teeth  require  removal,  and  not  the  bars  of  the 
mouth?  In  cutting  or  burning  away  lampas  we  mis- 
take the  effect  for  the  cause.  If  lampas  is  not  produced 
by  the  irritation  of  teething,  then  I  would  like  to  be 
informed  what  does  cause  it." 

Prof.  Youatt  says  of  lampas  ("The  Horse,"  p.  219); 

"It  may  arise  from  inflammation  of  the  gums, 
propagated  to  the  bars  when  the  colt  is  shedding  his 
teeth — young  horses  being  more  subject  to  it  than 
others — or  from  some  febrile  tendency  in  the  consti- 
tution generally,  as  when  a  young  horse  has  lately 
been  taken  from  grass,  and  has  been  over-fed  or  insuf- 
ficiently exercised.     It  is  well  to  examine  the  grinders, 


MASHES  AXD   LANCING   RECOMMENDED.  91 

and  more  particularly  the  tushes,  in  order  to  ascertain 
whether  they  are  making  their  way  through  the  gums. 
If  so,  incisions  should  be  made  across  the  swollen 
gums,  and  immediate  relief  will  follow.  At  times  it 
appears  in  aged  horses,  the  process  of  growth  in  the 
teeth  of  the  horse  continuing  during  life. 

"The  brutal  custom  of  farriers,  who  sear  and  burn 
the  bars  with  a  red  hot  iron,  is  most  objectionable.  It 
is  torturing  the  horse  to  no  purpose,  and  may  do  seri- 
ous injury.  In  a  majority  of  cases  the  swelUng  will 
subside  without  medical  treatment.  A  few  mashes 
and  gentle  alteratives  will  give  relief,  but  sometimes 
slight  incisions  across  the  bars  with  a  lancet  or  pen- 
knife may  be  necessary.  Indeed,  scarification  of  the 
bars  in  lampas  will  seldom  do  harm,  though  it  is  not 
as  necessary  as  is  generally  supposed." 

Concerning  "Diseases  occurring  during  Dentition" 
Prof.  William  Williams  says  ("  Principles  and  Practice 
of  Veterinary  Surgery,"  p.  476) : 

"In  the  horse  the  temporary  grinders  are  replaced 
by  permanent  ones  when  he  is  from  three  to  four  years 
old,  and  in  the  ox  at  from  two  years  and  six  months 
to  two  years  and  nine  months.  In  cattle  tlie  cutting 
of  the  permanent  molars  is  occasionally  a  matter  of 
some  difficulty  owing  to  the  unshed  crowns  of  the 
temporary  teeth  becoming  entangled  with  the  new 
teeth,  and  thus  proving  a  source  of  irritation  and  pre- 
venting the  animal  from  feeding.  In  some  parts  of 
the  country  such  animals  are  culled  ^rotten,'  from  their 
emaciated  condition,  and  perhaps  from  the  fetor  ema- 
nating from  the  mouth.  When  cattle  of  this  age  stop 
feeding,  lose  condition,  or  drivel  from  the  mouth,  the 


92  THE  CAXIXE  TEETH. 

teeth  should  be  examined,  and  if  the  unshed  molars 
are  causing  irritation,  they  should  be  removed  with 
the  forceps.  Hundreds  of  young  cattle  have  been  sac- 
rificed from  this  cause— actually  dying  of  starvation. 
In  the  horse  the  same  condition  of  the  grinders  may 
exist,  but  it  is  very  unusual.  The  corner  incisors, 
however,  may  present  the  same  anomalous  condition. 
Horses  from  four  years  to  four  years  and  six  months 
old  should  have  their  teeth  examined  occasionally  to 
see  if  all  is  going  on  w^ell. 

"  Horses  at  four  years  old  are  subject  to  a  distressing 
cough.  At  this  age  the  third  temporary  grinder  is 
replaced  by  its  permanent  successor,  and  at  the  same 
time  the  sixth  grinder  is  being  cut.  Some  irritation 
exists  in  the  gums  during  the  eruption  of  all  the  teeth, 
and  in  some  instances  it  is  excessive,  extending  from 
the  gums  to  the  fauces  and  larynx.  This  is  particu- 
larly the  case  with  the  sixth  grinder,  and  as  a  result  of 
the  extension  of  the  irritation,  cough  is  excited,  usually 
in  the  morning,  when  the  animal  begins  to  feed.  It 
is  loud,  sonorous,  and  prolonged,  the  horse  frequently 
coughing  twenty,  thirty,  or  even  forty  times  without 
ceasing.  It  is  a  throat  cough,  originating  in  laryngeal 
irritation. 

"The  treatment  for  this,  which  may  be  truly  said  to 
be  a  tooth-cough,  is  careful  dieting  on  crushed  food; 
hay,  not  much  bran  ;  grass,  if  in  season,  or  roots  if 
grass  is  not  obtainable ;  alkaline  medicines,  more  par- 
ticularly the  bicarbonate  of  soda;  gentle  aperients 
occasionally,  if  the  bowels  be  irregular.  If  the  faeces 
are  fetid  the  fetor  will  be  much  diminished  by  a  few 
doses  of  the  hyposulphite  of  soda,  the  mouth  to  be  gar- 
gled with  some  cooling  mixture,  such  as  the  borate  of 
soda  or  alum." 


DEXTITIOX   FEVER.  93 

Of  "Dentition  Fevsr"  Prof.  Williams  says  ("Prin- 
ciples and  Practice  of  Veterinary  Surgery,"  p.  470) : 

"  Horses  from  three  to  four  years  old  are  more  sub- 
ject to  this  species  of  dental  irritation  than  those  of  a 
more  tender  age,  and  it  is  well  known  among  horsemen 
that  they  will  stand  more  fatigue  at  a  more  tender  age 
than  they  will  at  this.  The  reason  is  because  teething 
is  now  at  the  hight  of  its  activity.  When  the  animal 
is  three  years  old,  eight  permanent  grinders  are  being 
cut,  and  four  permanent  incisors  are  in  active  growth 
withm  the  jaws.  At  four  years  of  age  the  same  num- 
ber of  grinders  are  out,  and  the  same  number  of  inci- 
sors are  at  a  more  advanced  stage  of  growth  within  the 
jaws,  in  addition  to  the  canine  teeth,  which  make 
their  appearance  about  this  time. 

"  No  wonder  then  that  the  eruption  of  so  many  teeth 
is  a  source  of  irritation  and  fever.  The  best  treatment 
is  to  throw  the  animal  off  work,  turn  him  to  grass  if 
the  weather  permits,  or  into  a  loose  box  in  a  well  ven- 
tilated spot,  and  give  him  rest  until  the  process  of  den- 
tition is  completed.  If  the  gums  are  red  and  swollen, 
lancing  them  will  prove  a  source  of  great  relief." 

On  page  503  Prof.  Williams,  in  speaking  of  crib- 
biting  and  wind-sucking,  says:  "Want  of  work  and 
the  irritation  of  teething  are  generally  the  causes  of 
these  vices." 


CHAPTER    V. 

THE    EEMKANT    TEETH. 

Usually  regarded  as  Plienomenons. — The  Name. — Traced  to 
tlie  Fossil  Horses,  in  which  (in  the  Pliocene  Period)  they 
"Ceased  to  be  Functionally  Developed." — Nature's  Meta- 
morphoses.— "  The  Agencies  which  are  at  work  in  Modeling 
Animal  and  Vegetable  Forms." — Why  Remnant  Teeth  are 
often,  as  it  were,  Prematurely  Lost. — Fossil  Horses  and  a 
Fossil  Toothed -Bird. 

The  Remnant  or  "so-called  wolf-teeth"  are  one  of 
the  most  interesting  features  of  the  horse's  dental  sys- 
tem. They  are  generally  regarded  as  phenomenons, 
but  their  line  of  descent  is  as  direct  as  that  of  the  first 
premolars  (grinders),  which  liave,  as  it  were,  almost 
absorbed  them,  and  have  increased  in  bulk  nearly  in 
proportion  to  the  decrease  in  bulk  of  the  Remnant 
teeth. 

As  the  word  "  wolf"  is  another  name  for  that  which 
is  hurtful  or  destructive,  and  as  these  teeth  as  well  as 
supernumerary  teeth,  with  which,  however,  they  should 
never  be  confounded,  sometimes  do  injury,  the  generic 
name,  "  wolf-teeth,"  is  not  a  bad  one.  But,  since  these 
particular  teeth  are  hereditary,  being  beyond  doubt  the 
remains  of  teeth  that  were  once  functionally  developed, 
they  require  a  specific  name ;  I  have  therefore  adopted 
the  name  Remkaj^^t  Teeth. 


PROF,  marsh's  researches.  95 

In  the  evolution  of  the  horse  from  an  animal  of 
about  the  size  of  a  fox  to  his  present  proportions,  it  is 
not  strange  that  radical  physical  changes,  of  the  teeth 
as  well  as  otlier  organs,  should  have  occurred,  or  that 
they  are  in  harmony  with  his  bodily  requirements  as 
well  as  his  usefulness  to  man.  Small,  four-toed  limbs 
would  support  the  body  of  an  animal  no  larger  than  a 
fox  or  a  sheep,  but  they  would  require  additional  size 
and  strength  to  support  the  small  horse  (Hipparion) 
of  the  Pliocene  period,  or  the  large  horse  of  the  present 
period  (Equus).  This  additional  strength  was  gradu- 
ally acquired  by  the  enlargement  of  the  limbs  and  the 
sohdification,  as  it  were,  of  four  toes  into  one,  it  being 
as  natural,  in  conformity  to  the  law  of  adaptation,  for 
a  line  of  succeeding  animal  forms  to  undergo  bodily 
changes  as  for  an  individual  form  to  do  so. 

During  these  metamorphoses  equally  varied  and 
interesting  changes  occurred  in  the  horse's  dental  sys- 
tem, which  are  described  by  Prof.  O.  C.  Marsh,  of  Yale 
College,  in  the  article  "Horse,  Fossil,"  in  "Johnson's 
New  Universal  Cyclopedia  (vol.  ii,  p.  906).  He  gives  a 
general  description  of  the  changes  that  have  occurred 
in  species  of  three  geological  periods,  namely,  the 
Pliocene,  Miocene,  and  Eocene,  those  of  the  two  last 
named  having  forty-four  functionally  developed  teeth. 
Th ft  part  of  the  article  which  refers  to  the  teeth  is  as 
follows : 

"In  the  Pliocene  tertiary  period  the  horse  was  rep- 
resented by  several  extinct  genera,  the  best  known  be- 
ing Hipparion  (or  Hippotherium).  The  species  are 
small,  as  the  name  implies,  Hipparion  being  a  dimin- 
utive from  the  Greek  hijipos,  a  Miorse.'  In  the  upper 
molar  teeth  there  is  in  Hipparion,  on  the  anterior  por- 


96  THE  rem:n^a2nT  teeth. 

tion  of  the  inner  side,  an  isolated  ellipse  of  enamel 
inclosing  dentine,  and  not  joined  with  the  main  body 
of  the  tooth  by  an  isthmus  of  dentine,  as  in  Equus,  at 
least  until  the  teeth  are  nearly  worn  out.  Anchippus, 
also  from  the  Pliocene,  resembled  in  its  teeth  Anchi- 
therium  of  the  Miocene,  a  genus  now  considered  as 
typical  of  a  family  distinct  from  that  of  the  horse.  In 
Anchitherium  the  molars  have  short  crowns,  devoid  of 
cement,  and  are  inserted  by  distinct  roots.  The  Mio- 
cene species  were  not  larger  than  a  sheep.  The  Eocene 
representatives  of  the  group  were  still  smaller,  the 
largest  hardly  exceeding  a  fox  in  size.  They  belong 
to  the  genus  Orohippus.  The  dentition  is  very  simi- 
lar to  that  of  Anchitherium,  but  the  first  upper  pre- 
molar is  larger  and  the  succeeding  ones  smaller  than 
in  that  genus.  The  diastema,  or  '  place  for  the  bit,'  is 
distinct.  The  canines  are  large,  and  near  the  incisors. 
The  crowns  of  the  molars  are  short  and  destitute  of 
cement,  and  the  skeleton  is  decidedly  equine  in  its 
general  features. 

"  The  gradual  elongation  of  the  head  and  neck  may 
be  said  to  have  already  begun  in  Orohippus,  if  we 
compare  that  form  with  other  most  nearly  allied  mam- 
mals. The  diastema  was  well  developed  even  then,  but 
increased  materially  in  succeeding  genera.  The  num- 
ber of  teeth  remained  the  same  until  the  PJiocene, 
when  the  front  lower  i^remolar  ivas  lost,  and  suhse- 
quentJy  the  corresponding  upper  tooth  ceased  to  he  func- 
tionally developed.'''  The  next  upper  premolar,  which 
in  Orohippus  was  the  smallest  of  the  six  posterior 

•^  The  italics  are  mine.  This  "  corresponding  upper  tooth 
that  ceased  to  be  functionally  developed,"  is  the  identical  tooth 
that  now  appears  as  a  mere  remnant. 


THE  LAEGE  TUSHES  OF  OROHIPPUS.       97 

teeth,  rapidly  increased  in  size,  and  finally  became  the 
largest  of  tlie  series.  The  grinding  teeth  had  at  first 
very  siiort  crowns,  without  cement,  and  were  inserted 
by  distinct  roots.  In  Pliocene  species  the  molars  be- 
came longer,  and  were  more  or  less  coated  with  cement. 
The  modern  horse  has  very  long  grinders,  without 
true  roots,  which  are  covered  with  a  thick  external 
layer  of  cement.  The  large  canines  of  Orohippus  be- 
came gradually  reduced  in  the  later  genera,  and  the 
characteristic  *mark'  upon  the  incisors  is  found  only 
in  the  later  forms.  It  is  an  interesting  fact  that  the 
peculiarly  equine  features  acquired  by  Orohippus  are 
retained  persistently  throughout  the  entire  series  of 
succeeding  forms."  * 

*  "The  ancient  Orohippus  liad  all  four  digits  of  the  fore-feet 
well  developed.  In  Mesohippus,  of  the  next  period,  the  fifth 
toe  is  only  represented  by  a  rudiment,  and  the  limb  is  supported 
by  the  second,  third,  and  fourth,  the  middle  one  being  the 
largest.  Hipparion  of  the  Later  Tertiary  still  has  three  digits, 
but  the  third  is  much  stouter,  and  the  outer  toes  have  ceased  to 
be  of  use,  as  they  do  not  touch  the  ground.  In  Equus  the  lat- 
eral hoofs  are  gone,  and  the  digits  themselves  are  represented 
only  by  the  rudimentary  splint-bones.  The  middle  or  third 
digit  supports  the  Umb,  and  its  size  has  increased  accordingly. 
The  corresponding  changes  in  the  posterior  limb  of  these  genera 
are  very  similar  but  not  so  striking,  as  the  oldest  type  (Orohip- 
pus) had  but  three  toes  behind.  The  earlier  ancestor  of  the 
gfroup,  perhaps  in  the  lowest  Eocene,  probably  had  four  on  this 
foot  and  five  in  front.  Such  a  predecessor  is  as  clearly  indicated 
by  the  feet  of  Orohippus  as  the  latter  is  by  its  Miocene  relative. 
A  still  older  ancestor,  possibly  in  the  Cretaceous,  doubtless  had 
five  toes  on  each  foot,  the  typical  number  in  mammals.  This 
reduction  in  the  number  of  toes  may  perhaps  have  been  due  to 
elevation  of  the  region  inhabited,  which  gradually  led  the  ani- 
mals to  live  on  higlier  ground,  instead  of  the  soft  lowlands, 
where  a  many-toed  foot  would  be  most  useful." — Prof.  0.  (7. 
Marsh. 


98  THE    RE1[:>AXT  TEETH. 

The  article  closes  as  follows: 

''Such  is,  in  brief,  a  general  outline  of  the  more 
marked  changes  that  appear  to  have  produced  in 
America  the  highly  specialized  modern  Equus  from 
its  diminutive,  four-toed  predecessor,  the  Eocene  Oro- 
hippus.  The  line  of  descent  appears  to  have  been 
direct,  and  the  remains  now  known  supply  every  im- 
portant intermediate  form.  Considering  the  remark- 
able development  of  the  group  throughout  the  entire 
tertiary  period,  and  its  existence  even  later,  it  seems 
very  strange  that  none  of  the  species  should  have  sur- 
vived, and  that  we  are  indebted  for  our  present  horse 
to  the  Old  World."* 

*  The  follo^viag  extracts  from  Prof.  C.  S.  Tomes's  "Dental 
Anatomy,  Human  and  Comparative"  (pp.  247-8,  254-5),  explain 
some  of  the  causes  of  the  raetamorphos.^s  described  by  Prof. 
Marsh  ;  "  He  would  indeed  be  a  rash  man  who  ventured  to  as- 
sert that  we  had  recognized  all  the  agencies  which  are  at  work 
in  the  modeling  of  animal  and  vegetable  forms ;  but  it  is  safe  to 
say  that,  at  the  present  time,  we  are  acquainted  vnth  several 
agencies  which  are  in  constant  operation,  and  which  are  com- 
petent to  profoundly  modify  animals  in  successive  generations. 
We  know  of  'uaUiral  selection/  or  'survival  of  the  fittest,'  an 
agency  by  which  variations  beneficial  to  their  possessors  will  be 
preserved  and  intensified  in  successive  generations ;  of  *  sexual 
selection,'  which  operates  principally  by  enabling  those  pos- 
Sf^ssed  of  certain  characters  to  propagate  their  race,  while  others 
less  favored  do  not  get  the  opportunity  of  so  doing-;  of  'con- 
comitant variation'  between  different  parts  of  the  body,  an 
agency  much  more  recondite  in  its  operations,  but  by  which 
agencies  affecting  one  part  may  secondarily  bring  about  altera- 
tions in  some  other  part. 

"The  doctrine  of  natural  selection,  or  survival  of  the  fittest, 
is  as  applicable  to  the  teeth  of  an  animal  as  to  any  part  of  its 
organization,  and  the  operation  of  this  natural  law  will  be  con- 
stantly tending  to  produce  advantages  or  'adaptive'  differences. 
On  the  other  hand,  tlie  strong  power  of  inheritance  is  tending  to 


KOT  LAKE,  EL'T  EASILY  LOST.  G9 

Remnant  teeth  are  not  rare,  but  it  is  rare  for  them 
to  persist  in  the  jaws  till  even  middle  age.     However, 

prsserve  even  that  which,  in  the  altering  conditions  of  life,  has 
become  of  very  11  ttle  us?.  Thus  we  may  un  ;lerstand  rudimentary 
teeth  to  he  teeth  which  are  in  process  of  disappearance,  having 
ceased  to  be  useful  to  tlieir  possessors,  but  still  for  a  time, 
through  the  influence  of  inheritaucs,  lingering  upon  the  scene. 
Some  teeth  have  disappeared  utterly.  Thus  the  upper  incisors 
of  ruminants  are  gone,  and  no  rudiments  exist  at  any  stage ; 
others  still  remain  in  a  stunted  form,  and  do  not  persist  through- 
out the  lifetime  of  the  animal,  as,  for  instance,  the  first  premo- 
lars of  the  horse,  or  two  out  of  the  four  premolars  of  most  bears. 

"  Teeth  are  profoundly  susceptible  of  modification,  but  amid 
all  their  varied  forms,  the  evidences  of  descent  from  ancestors 
whose  teeth  departed  less  from  the  typical  mammalian  dentition 
are  clearly  traceable  by  the  existence  of  rudimentary  teeth  and 
other  such  characters.  *  *  *  The  power  of  inheritance  is 
constantly  asserting  itself  by  the  retention,  for  a  time  at  least, 
of  parts  wliicli  have  become  useless,  and  by  the  occasional  reap- 
pearance of  characters  which  have  been  lost.  *  *  *  Things 
that  are  rudimentary  often  teach  us  most ;  for  being  of  no  pres- 
ent use,  they  are  not  undergoing  that  rapid  change  in  adaptation 
to  the  animal's  habits  which  may  be  going  on  in  organs  that 
are  actively  employed." 

I^orses  are  not  the  only  animals  that  have  had  or  are  having 
changes  in  their  dentition.  Mr.  C.  R.  Darwin  says  ("  Descent  of 
Man,"  vol.  i,  p.  25):  "It  appears  as  if  the  posterior  molar  or 
wisdom-teeth  were  tending  to  become  rudimentary  in  the  more 
civilized  races  of  men.  They  are  rather  smaller  than  the  other 
teeth.  In  the  Melanian  races,  on  the  other  hand,  the  ^\isdom- 
testh  are  usually  furnished  v/ith  three  separate  fangs,  are  gen- 
erally sound,  and  differ  in  size  from  the  other  molars  less  than 
in  the  Caucasian  races.  Prof.  Schaaffhausen  accounts  for  this 
difference  between  the  races  by  'the  posterior  dental  portion  of 
the  jaw  being  always  shortenerl'  in  those  that  are  civilized,  and 
this  shorteninsr  may,  I  presume,  be  safelv  attributed  to  civilized 
men  habitually  feeding  on  soft,  cooked  food,  and  thus  using 
their  jaws  l3ss.  I  am  informed  by  Mr.  Brace  that  it  is  becoming 
quite  a  common  praciice  in  the  United  States  to  remove  some 


100  THE  EEMNAXT  TEETH. 

there  may  be  cases  where  they  never  appear;  but  it 
by  no  means  follows  that  because  a  horse  is  not  in  pos- 
session of  them  that  he  never  had  any.  There  are 
various  causes  for  their  frequent  absence,  but  the  chief 
cause  is  their  small  size.  Remnant 
teeth  of  the  lower  jaw,  which  are 
very  rare,  are  probably  cases  of  ^'  re- 
version to  a  former  state."  *  If  these 
latter  teeth  were  not  expelled  in  the  ^^^^^^.^,  ,^^^^ .  ^^,^^,,.^^ 
manner  explained  below  by  Mons.  ^^^^-onyinai. 

Lecoq,  the  probability  is  that  they  would  not  long 
withstand  the  friction  of  the  bit.  The  upper  teeth, 
hov/ever,  while  they  may  sometimes  be  expelled  by  the 
bit,  are  comparatively  little  disturbed  by  it,  which 
probably  accounts  for  their  now  and  then  remaining 
in  the  jaws  for  years.  Another  reason  for  their  per- 
sistence is  that  their  roots  are  long  in  proportion  to 
their  bodies.  The  reason  why  these  teeth  should  not 
be  confouuded  with  supernumerary  or  abnormal  teeth 
will  appear  ni  the  succeeding  chapter,  which  is  devoted 
to  the  consideration  of  the  latter. 

Monsieur  Lecoq  gives  cogent  reasons  for  the  fre- 
quent absence  of  Remnant  teeth.     He  says: 

"  Supplementary  molars  are  sometimes  met  with  in 
front  of  the  true  ones,  and  there  may  be  four  of  them, 
two  in  either  jaw,  above  and  below.  They  are  small 
teeth,  having  but  little  recemblance  to  the  others,  are 
frequently  shed  with  the  first  deciduous  molar,  and 
are  not  replaced.  The  first  replacing  (permanent) 
molar  is  always   a  little  more  elongated   than   that 

of  the  molar  teeth  of  childran,  as  the  jaw  does  not  grow  largo 
enouo;h  for  the  perfect  development  of  the  normal  number." 
*  See  the  second  reference  note,  page  80. 


HOW  THEY  MAY   BE   LOST.  101 

which  it  succeeds,  and  it  frequently  expels  at  the  same 
time  the  supplementary  molar;  so  that  if  forty-four 
teeth  be  deyeJoped  in  the  male  horse,  it  is  very  rare 
that  they  are  all  present  at  the  same  time." 

That  Kemnant  teeth  are  usually  regarded  as  phe- 
nomenons  is  abundantly  proved  by  some  of  the  ex- 
tracts that  follow.  In  "Johnson's  New  Universal 
Cyclopedia"  (p.  995),  article  "Horse,"  it  is  said: 

"  Au  additional  small  tooth  is  occasionally  found  iu 
advance  of  the  upper  molar  series.  This  tooth,  when 
present,  is  the  smallest  of  all  the  teeth,  and,  as  it  has 
neither  predecessor  nor  successor,  its  nature  is  in 
doubt." 

As  the  nature  of  these  teeth  appeared  to  be  clearly 
explained  in  the  article  "  Horse,  Fossil,"  which  imme- 
diately follows  that  on  tlie  "  Horse,"  I  wrote  to  Prof. 
Joseph  Leidy,  telling  him  I  believed  the  "wolf-teeth" 
were  the  remnants  of  the  teeth  that  "ceased  to  be 
functionally  developed,"  and  asked  his  opinion  about 
the  matter.  Writing  under  date  of  "Philadelphia, 
Nov.  26,  1878,"  he  said: 

*  *  *  "I  think  you  are  right  in  supposing  that 
tlie  little  premolars  referred  to  by  Prof.  Marsh  as  the 
^  corresponding  upper  teeth,'  which  ^ceased  to  be  func- 
tionally developed,'  are  the  so-called  ^wolf-teeth.'" 

Another  letter,  addressed  to  Prof.  Theodore  Gill, 
elicited  the  following  reply,  vvhich  was  dated  "Smith- 
sonian Institution,  Washington,  D.  C,  Nov.  25, 1878:" 

*  *  ^  u  ^]^g  complete  dentition  of  the  adult 
horse  is  represented  by  the  formula:  I.,  |;  C.  i; 
D.,  i;   P.  M.,  I;   M.,  -|x2  =  42.     The  'small  wolf  or 


102  THE   REMNANT  TEETH. 

siiperni-imerary  tooth  tbat  appears  in  front  of  the  first 
upper  premolar,'  is  the  more  or  less  persistent  first 
deciduous  molar  (d  1)  of  the  first  series,  which  is  not 
succeeded  by  a  first  premolar.  The  premolars  are  con- 
sequently P.  M.,  2,  3,  and  -i  of  the  typical  educabilian 
dentition.^' 

Prof.  Pvichard  Owen,  who,  like  Drs.  Gill  and  Leidy, 
has  a  clear  conception  of  the  subject,  says: 

"  The  second  incisor  appears  between  the  twentieth 
and  fortieth  days,  and  about  this  time  the  first  small, 
deciduous  premolar  takes  its  place.  *  *  *  The 
representative  of  the  first  premolar  is  a  very  small  and 
simple  rudiment,  and  is  soon  shed." 

Surgeon  Charles  Parnell,  in  a  letter  to  the  editor  of 
"The  Veterinarian"  (1867,  p.  287),  says: 

"In  reading  Prof.  George  Varnell's  articles  on  some 
of  the  diseases  afi"ecting  the  facial  region  of  the  horse's 
head,  I  notice  a  description  of  wolf-teeth.  He  says : 
'They  have  been  supposed  to  be  the  cause  of  disease  in 
the  eyes  of  horses.  This  idea,  however,  is  quite  erro- 
neous; therefore  I  shall  not  occupy  any  space  in  dis- 
cussing this  traditional  error.'  Well,  I  can  safely  say 
that  I  have  in  my  time  extracted  a  great  many  of  these 
teeth,  and  not  merely  because  they  existed,  but  because 
there  was  a  weeping  from  both  eyes,  the  cause  of  wdiich 
was  attributed  to  wolf-teeth,  and  generally  in  the 
course  of  a  few  weeks  the  weeping  has  ceased.  But 
what  convinces  me  that  they  do  affect  the  eye  is  that 
in  several  cases  where  there  were  weeping  and  weak- 
ness of  one  eye  only,  I  have  found  a  wolf-tooth  on  the 
affected  side  only,  and  the  recovery  of  the  eye  has  in- 
variablv  followed  the  extraction  of  the  tooth.     The 


HORSES   WITHOUT   EARS.  103 

mucous  membranes  and  lachrymal  glands  appear  to 
be  the  parts  aifected,  undoubtedl}^  from  some  connec- 
tion through  the  nerves.  If  these  teeth  are  allowed  to 
remain  in  the  horse's  mouthy  the  sight  will  become 
more  or  loss  impaired." 

Might  not  this  plan  (extracting  tlie  teeth),  if  adopted 
by  all  surgeons,  eventuaiij  rid  horses  of  the  so-called 
wolf-teeth?  Nature  may  be  aided  or  injured.  Tlie 
effect  of  interfering  with  nature  is  illustrated  by  the 
following  extract  from  Prof.  W.  Youatt's  work,  '•  The 
Horse"  (p.  154): 

"  The  custom  of  cropping  tlie  ears  of  the  horse  orig- 
inated, to  its  shame,  in  Great  Britain,  and  for  many 
years  was  a  practice  not  only  cruel  to  the  animal,  but 
deprived  it  of  much  of  its  beauty.  It  was  so  obsti- 
nately persisted  in  that  at  lengtii  the  deformity  be- 
came in  some  hereditary,  and  a  breed  of  horses  born 
without  ears  was  produced." 

Extracting  the  Eemnant  teeth  appears  to  aid  rather 
than  injure  nature.  The  practice  is  therefore  as  com- 
mendable as  the  cropping  of  the  ears  is  reprehensible, 
and  if  the  same  result  should  follow  that  Prof.  Youatt 
says  followed  the  cropping  of  the  ears,  it  ought  to  be 
adopted. 

C.  D.  House,  an  American  veterinary  dentist,  like 
Surgeon  Parnell,  invariably  extracts  the  Eemnant 
teeth.  He  not  only  claims  that  they  sometimes  injure 
the  eyes,  but  that  in  some  cases,  when  they  encroach 
on  the  maxillary  branch  of  the  fifth  pair  of  nerves, 
they  cause  the  horse  to  act  as  iF  insane.  He  says  he 
has  more  than  once  extracted  these  teeth  when  the 
"insane"  horse  w^as  in  an  onen  field.     When  the  tooth 


104  THE   REMXAXT  TEETH. 

is  drawn  and  the  animal  is  relieved,  it  looks  around 
and  stares  and  acts  as  if  wondering  where  it  is  and  how 
it  got  there.  Not  more  than  one  horse  in  twenty  pos- 
sessing these  teeth,  he  says,  ever  suffers  injury  to  its 
eyes. 

Surgeon  E.  Jennings  of  Detroit  has  examined  many 
fetuses  and  always  found  Remnant  teeth  germs  ;  dur- 
ing 37  years'  practice,  in  more  than  100  deaths  under 
two  years,  not  a  single  instance  occurred  where  these 
teeth,  or  the  germs  which  produce  them,  were  not 
found.  They  will  be  found  usually  at  the  age  of  two 
years. 

Veterinary  Dentist  J.  Ramsey  of  Boston  treated  a 
7-year-old  horse  in  1881  that  had  been  "  out  of  con- 
dition "  for  several  years,  and  consequently  had  had 
several  owners.  He  discovered  a  long  Remnant  tooth 
with  such  a  vicious  inclination  toward  the  roof  of  the 
mouth  as  to  interfere  with  the  use  of  the  tongue.  As 
soon  as  the  tooth  was  extracted  the  horse  began  to  eat. 

Prof.  Williams  savs  of  Remnant  teeth  ("Principles 
and  Practice  of  Veterinary  Surgery,"  p.  479) : 

"  Small  supernumerary  teeth  are  often  met  with  in 
front  of  the  grinders,  called  *  wolf-teeth.'  They  have 
been  supposed  to  be  a  cause  of  ophthalmia,  but  this  is 
doubtful.  They  can  produce  no  inconvenience;  but 
if  requested  to  extract  them  a  practitioner  can  liardly 
refuse.  The  best  method  is  to  remove  them  with  the 
tooth-forceps. 

"The  question  as  to  the  influence  of  the  teeth  on 
the  eyes  miglit  perhaps  be  deemed  worthy  of  discus- 
sion, inasmuch  as  the  dental  nerve  is  a  branch  of  that 
which  supphes  the  eyes  with  common  sensibihty, 
namely,  the  fifth.     The  older  writers  maintained  that 


MOOX-BLIXDXESS.  105 

^moon-blinduess'  was  due  to  wolf-teeth,  and  the  first 
procedure  in  the  treatment  was  their  removal.  Now- 
adays, however,  the  supposition  is  not  carried  quite  so 
far,  and  the  utmost  that  can  be  said  is  that  the  irrita- 
tion of  teething  may  be  an  exciting  cause  of  ophthal- 
mia in  animals  whose  constitutions  are  hereditarily  or 
otherwise  predisposed  to  the  disease,  and  the  removal 
of  supernumerary  teeth,  or  lancing  the  gums,  may  pos- 
sibly be  followed  by  some  remission  of  the  ophthalmic 
symptoms." 

Prof.  Youatt  thus  accounts  for  Remnant  teeth : 

"  In  a  few  instances  the  permanent  teeth  do  not  rise 
immediately  under  the  temporary,  but  somewhat  by 
their  side.  Then,  instead  of  the  gradual  process  of  ab- 
sorption, the  root,  being  compressed  sideways,  dimin- 
ishes throughout  its  whole  bulk.  The  crown  dimin- 
ishes also,  and  the  tooth  is  pushed  out  of  its  place  to 
the  forepart  of  the  first  grinder,  and  remains  for  a  con- 
siderable time  under  the  name  of  a  wolf-tootli,  causing 
swelling  and  soreness  of  the  gums,  and  frequently 
wounding  the  cheeks.  They  would  be  gradually  quite 
absorbed,  but  the  process  might  be  slow  and  the  an- 
noyance great;  therefore  they  are  extracted." 

Prof.  Youatt's  theory  is  unique,  but  it  fails  to  give 
a  satisfactory  explanation  of  the  "so-called  wolf-teeth." 
That  a  tooth  should  be  pushed  out  of  its  place  is  sim- 
ple enough  ;  but  wliy  would  the  first  upper  temporary 
grinder  remain  in  the  gum  and  take  root  and  the  first 
lower  not?  That  "they  would  be  gradually  quite  ab- 
sorbed," is  disproved  by  the  fact  that  they  sometimes 
persist  till  old  age;  and  this  fact  also  disproves  the 
assertion  that  "they  are  extracted."     Some  surgeons 


106  FOS:iL  II0I13ES'  TEETH. 

do  not  extract  them.     Prof.  Yotiatt  doubtless  meant 
to  say  they  should  be  extracted. 

As  Eemnant  teeth  are  found  functionally  devel- 
oped in  the  jaws  of  fossil  horses — in  which  they  were 
the  largest  of  all  the  teeth — a  few  extracts  from  the 
works  of  well-known  men  concerning  fossil  horses  and 
their  teeth  will  be  appropriate  as  a  conclusion  to  this 
chapter.  Prof  Kichard  Owen  says  ("Odontography," 
vol.  i,  p.  575): 

"  Cuvier  was  unable,  from  the  materials  at  his  com- 
mand, to  detect  any  characters  in  the  bones  or  teeth 
of  the  different  existing  species  of  Equus,  or  in  the 
fossil  remains  of  the  same  genus,  by  which  he  could 
distinguish  them,  save  by  their  difference  of  size. 
Among  the  numerous  teeth  of  a  species  o{  Equus  as 
.  large  as  a  horse  fourteen  and  a  half  hands  high,  col- 
lected from  the  Oreston  cavernous  fissures,  1  have 
found  specimens  clearly  indicating  two  distinct  spe- 
cies, so  fiLir  as  specific  differences  may  be  founded  on 
well-marked  modifications  of  the  teeth. 

"One  of  these,  like  the  ordmB^ij  Fquus  fossilis  of 
the  drift  and  pleistocene  formations,  differs  from  the 
existing  Equus  cabalhcs  by  the  minor  transverse  diam- 
eter of  the  molar  teeth;  the  other,  in  the  more  com- 
plex and  elegant  plication  of  the  enamel,*  and  in  the 

*  In  Prof.  Owen's  "  History  of  British  Fossil  Mammals  and 
Birds"  (pp.  39;J-4),  the  "  eh^gaut  plication  of  the  enamel"  on 
the  Grown  of  this  tooth  is  illustrated.  Prof.  Owen  says  :  "  Fig. 
153  illustrates  the  character,  ahove  adverted  to,  of  the  complex 
plication  of  the  enamel,  as  it  appears  on  the  g-rinding-  surface  of 
a  partially  worn  upper  molar  tooth,  the  second  of  the  right  side. 
Tlie  length  of  this  tooth  is  three  inches  four  lines,  and  the  fangs 
had  not  begun  to  be  formed.  One  cannot  view  the  elegant  fold- 
ings of  the  enamel  ia  the  present  fossil  teeth,  and  in  those  of 


TEETH  uxea:.t:izd  J 


iT   ORESTOX,  ENG.  lOT 


biiobed  posterior  termination  of  tlie  grinding  surface 
of  tiie  last  upper  molar,  more  closely  approximates  to 
the  extinct  horse  of  the  Miocene  period,  winch  Herr 
von  Meyer  has  characterized  under  t!ie  name  of  Eqmis 
cctbaUus  primigenius.  The  Oreston  fossil  teeth  differ, 
however,  from  tliis  in  the  form  of  the  tifth  or  internal 
prism  of  dentine  in  the  upper  molars,  and  in  its  con- 
tinuation with  the  anterior  lobe  of  the  teeth,  the  fifth 
prism  being  oval  and  insulated  in  the  Equus  inimi- 
(/cyz/^/s  of  Von  Meyer. 

'•The  Oreston  fossil  teeth,  which  in  their  principal 
characters  manifest  so  close  a  relatiouship  with  the 
Miocene  Equus  primigenius,  ^\'^^^^.  like  the  later  drift 
species  'yE^i.  fossilis),  from  the  recent  horse  in  a  greater 
proportional  antero-posterior  diameter  of  the  crown, 
and  also  in  a  less  produced  anterior  angle  of  the  first 
premolar.  I  have  named  this  British  fossil  horse 
Equus  plicidens.  The  fossil  horse  {Eq.  cnrvidens)  of 
South  America,  which  coexisted  with  the  megathe- 
rium,! and,  like  it,  became  extinct  apparently  before 

the  more  ancient  primigenial  species  (Hippotlieria)  of  the  conti- 
nental Miocene  deposits,  without  being  reminded  of  the  peculiar 
character  of  the  enamel  of  the  molars  of  the  Elasmotherium,  in 
which  it  is  folded  in  elegant  festoons.  This  extinct  pachyderm, 
which  surpassed  the  rhinoceros  in  size,  resembled  that  genus 
very  closely  in  the  general  disposition  of  the  folds  of  enamel  in 
the  grinding  teeth,  but  agreed  with  the  modern  horse  in  the 
deep  implantation  of  those  teeth  by  an  undivided  base.  The 
EUismothere  appears,  therefore,  to  have  formed  one  of  the  links, 
now  lost,  which  connected  the  horse  with  the  rhinoceros  ;  and 
it  is  interesting  lo  observe  that  some  of  the  extinct  species  of 
horse,  in  the  analogous  complexity  of  the  enamel  folds,  more 
closely  resembled  the  Elasmothere  than  do  the  present  species." 
f  "  The  teeth  of  this  most  gigantic  of  the  extinct  quadrupeds 
of  the  sloth  tribe  are  small  in  proportion  to  the  size  of  the  ani- 


108  FOoSIL  IIOIISES'  TEETH. 

the  iutroduction  of  the  human  race,  differs  from  the 
existing  horse  by  the  greater  degree  of  curvature  of 
the  upper  molars." 

The  following  account  of  two  fossil  molar  teeth  of  an 
extinct  species  of  horse,  discovered  in  South  America, 
may  be  found  in  Prof.  Owen's  "Fossil  Mammaha  and 
Mammaha /'  (pp.  108-9) : 

''Notice  of  the  remains  of  a  impedes  of  Equus,  found 
associated  with  the  extinct  Edentcds  and  Toxodon  at 
Punta  Attay  in  Bahia  Blanca,  and  loith  the  Mastodon 
and  Toxodon  at  Santa  Fe,  in  Entre  Rios. — The  first  of 
these  remains  is  a  su}:>erior  molar  tooth  of  the  right 
side.  It  was  imbedded  in  the  quartz  shingle,  formed 
of  pebbles  strongly  cemented  together  with  calcareous 
matter,  which  adhered  as  closely  to  it  as  the  corre- 
sponding matrix  did  to  the  associated  fossil  remains. 
The  tooth  was  as  completely  fossilized  as  the  remains 
of  the  mylodon,  megatherium,  and  scelidothere,  and 
was  so  far  decomposed  that  in  the  attempt  to  detach 
the  adherent  matrix  it  became  partially  resolved  into 
its  component  curved  lamellae.  Every  point  of  com- 
parison tliat  could  be  established  proved  it  to  differ 
from  the  tooth  of  the  common  Equiis  cdballus  only  in 
a  slight  inferiority  of  size. 

"The  second  evidence  of  the  coexistence  of  i\\^ 
horse  with  the  extinct  mammals  of  the  tertiary  epoch 
of  South  America  reposes  on  a  more  perfect  tooth, 
likewise  of  the  upper  jaw,  from  the  red  argillaceous 

mal.  They  are  five  in  number  on  each  side  of  the  upper  jaw, 
and,  probably,  four  on  each  side  of  the  lower.  They  present  a 
more  or  loss  tetragonal  tigure,  and  have  the  grinding  surface 
traversed  by  two  transverse  angular  ridges." — Owen. 


IX  SOUTH  AjIEKICA.  109 

earth  of  the  Pampns  at  Bojada  cle  Santa  Fe,  in  the 
Province  of  Entre  Rios.  This  tooth  agreed  so  closely 
in  color  and  condition  with  the  remains  of  the  masto- 
don and  toxodon,  from  the  same  locality,  that  I  have 
no  doubt  respecting  the  contemporaneous  existence  of 
the  individual  horse  of  which  it  once  formed  part. 
This  tooth  is  figured  at  Plate  xxxii,  Figs.  13  and  14, 
from  which  the  anatomist  can  judge  of  its  close  corre- 
spondence with  a  middle  molar  of  the  left  side  of  the 
upper  jaw. 

'^This  evidence  of  the  former  existence  of  a  genus 
which,  as  regards  South  America,  had  become  extinct, 
and  has  a  second  time  been  introduced  into  that  conti. 
nent,  is  not  one  of  the  least  interesting  points  of  Mr. 
Darwin's  paleontological  discoveries."  * 


*  Mr.  Darwin,  in  his  work  on  "  Tlie  Descent  of  Man"  (vol.  i, 
pp.  230-1),  says  :  "  Although  the  gradual  decrease  and  final  ex- 
tinction of  the  races  of  man  is  an  obscure  problem,  we  can  see 
that  it  depends  on  many  causes,  differing  in  different  places  and 
at  different  times.  It  is  the  same  difficult  problem  as  that  pre- 
sented by  the  extinction  of  one  of  the  higher  animals— of  the 
fossil  horse,  for  instance — which  disappeared  from  South  Amer- 
ica, soon  to  be  replaced,  within  the  same  districts,  by  countless 
herds  of  the  Spanish  horse." 

In  his  "Journal  of  Researches"  (pp.  130-1-2),  Mr.  Darwin 
gives  further  information  concerning  the  fossil  teeth  described 
by  Prof.  Owen,  and  advances  a  theory  of  the  introduction  of  the 
horse  into  the  "  so-called  New  World."  He  says :  "  In  the  Pam- 
pgean  deposit  of  the  Bojada  I  found  the  osseous  armor  of  a  gigan- 
tic, armadillo-like  animal,  the  inside  of  which,  when  the  earth 
was  removed,  was  like  a  ijreat  cauldron.  I  also  found  teeth  of 
the  toxodon  and  mastodon,  and  one  of  a  horse,  in  the  same 
stained  and  decayed  state.  The  latter  greatly  interested  me,  and 
I  took  scrupulous  care  in  ascertaining  that  it  had  been  im- 
bedded contemporaneously  with  the  other  remains ;  for  I  was 
not  then  aware  that  among  the  fossils  from  Bahia  Blanca  there 


110  FOSSIL  HORSES'  TEETH. 

Prof.  Thomas  H.  Huxley  says  (''  Critiques  and  Ad- 
dresses/' pp.  191-5) : 

"  Let  us  endeavor  to  find  some  cases  of  true  linear 
types,  or  forms  which  are  intermediate  between  others, 
because  they  stand  in  a  direct  genetic  relation  to  them. 
It  is  no  easy  matter  to  find  clear  and  unmistakable 
evidence  of  filiation  among  fossil  animals.    After  much 

was  a  horse's  tooth  hidden  in  the  matrix  ;  nor  was  it  then  known 
with  certainty  that  the  remains  of  horses  wore  common  in  North 
America.  Mr.  Lyell  has  lately  brought  from  tiie  United  States 
a  tooth  of  a  horse ;  and  it  is  an  interesting  fact  that  Prof.  Owen 
could  find  in  no  species,  either  fossil  or  recent,  a  slight  but  pecu- 
liar curvature  characterizing  it,  until  he  thought  of  comparing 
it  with  my  specimen  found  here.  Certainly  it  is  a  marvelous 
fact  in  the  history  of  the  Mammalia,  that  in  South  America  a 
native  horse  should  have  lived  and  disappeared,  to  be  succeeded 
in  after  ages  by  the  coimtless  herds  descended  from  the  few  in- 
troduced by  the  Spanish  colonists !  (I  need  hardly  state  here 
that  there  is  good  evidence  against  any  horse  living  in  America 
at  the  time  of  Columbus). 

"  When  America,  and  especially  North  America,  possessed  its 
elephants,  mastodons,  horse,  and  hollow-horned  ruminants,  it 
was  much  more  closely  relai:ed  in  its  zoological  characters  to  the 
temperate  parts  of  Europe  and  Asia  than  it  now  is.  As  the 
remains  of  these  genera  are  found  on  both  sides  of  Behring's 
Straits  and  on  the  plains  of  Siberia,  we  are  led  to  look  to  the 
nortliwestern  side  of  North  America  as  the  former  point  of  com- 
mimication  between  the  Old  and  the  so  called  New  World.  And 
as  so  many  species,  both  living  and  extinct,  of  these  same  genera 
inhabit  and  have  inhabited  the  Old  World,  it  seems  most  x^rob- 
able  that  the  North  American  elephants,  mastodons,  horse,  and 
hollow-horned  ruminants  migrated — on  land  since  submerged 
near  Behring's  Straits — from  Siberia  into  North  America,  and 
thence — on  land  since  submerged  in  the  West  Indies — into 
South  America,  where  for  a  time  they  mingled  with  the  forms 
characteristic  of  that  southern  continent,  and  have  since  become 
extinct." 


HIPPAEIOX  AND  A:>TCIIITHERIl-M.  Ill 

search,  hov^'ever,  I  think  that  such  a  case  is  to  be  made 
out  in  favor  oi  the  horses.  The  modern  horse  is  rep- 
resented as  far  back  as  the  latter  part  of  the  Miocene 
epoch;  bur-  in  deposits  belonging  to  the  middle  of  that 
epoch  its  phice  is  taken  by  t'»yo  other  genera,  Hipparion 
and  Anchitherium.  A  species  of  Anchitherium  was 
referred  by  Cuvier  to  the  Paleotheria.  The  grinding 
teeth  are  in  fact  ver}^  similar  in  shape  and  in  pattern, 
and  in  the  absence  of  any  thick  layer  of  cement,  to 
those  of  some  species  of  Paleotherium.  But  in  the 
fact  that  there  are  only  six  full-sized  grinders  in  the 
lower  jaw,  the  first  premolar  being  very  small;  that  the 
anterior  grinders  are  as  large  as  or  rather  larger  than 
the  posterior  ones;  that  the  second  premolar  has  an 
anterior  prolongation,  and  that  the  posterior  molar  of 
the  lower  jtiw  has,  as  Cuvier  pointed  out,  a  posterior 
lobe  of  much  smaller  size  and  different  form,  the  den- 
tition of  Anchitherium  departs  from  the  type  of  the 
Paleotherium  and  approaches  that  of  the  horse.  The 
skeleton  of  Anchitherium  is  extremely  equine. 

"In  the  Hipparion  the  teeth  nearly  resemble  those 
of  the  horse,  though  the  crowns  of  the  grinders  are  not 
so  long.  Like  those  of  the  horse,  they  are  abundantly 
coated  mth  cement.  In  the  modern  horse,  finally,  the 
crowns  of  the  grinding  teeth  become  longer,  and  their 
patterns  are  slightly  modified." 

Alfred  Eussel  Wallace,  F.E.G.S.,  &c.,  says  (--The 
Geographical  Distribution  of  Animals,"  ^N'ew  York 
edition,  vol,  i,  p.  135): 

''Ungulafa.—The  animals  belonging  to  this  order 
being  usually  of  large  size  and  accustomed  to  feed  and 
travel  in  herds,  are  liable  to  wholesale  destruction  by 
floods,  bogs,  precipices,  drought,  or  hunger.     It  is  for 


113  FOSSIL   HORSES. 

thesG  reasons,  probably,  that  their  remains  are  almost 
always  more  numerous  than  those  of  other  orders  of 
mammalia.  In  America  they  are  especially  abundant. 
"  The  true  horses  are  represented  in  the  Pliocene  by 
several  ancestral  forms.  The  most  nearly  allied  to  the 
modern  horse  is  Pliohippus,  consisting  of  animals 
about  the  size  of  an  ass,  with  lateral  toes  not  exter- 
nally developed,  bnt  with  some  differences  of  dentition. 
Next  come  Protohippus  and  Hipparion,  in  which  the 
lateral  toes  are  developed,  but  are  small  and  function- 
less,  Protohippus  being  only  two  feet  and  a  half  high. 
Tiien  we  have  the  allied  genera,  Anchippus,  Merychip- 
pus,  and  Hyohippus,  which  were  still  smaller  animals. 
In  the  older  deposits  we  come  to  a  series  of  forms,  still 
nnmistakably  equine,  but  with  three  or  more  toes  used 
for  locomotion,  and  vrith  numerous  differentiations  in 
form,  proportions,  and  dentition.  In  the  Miocene  we 
have  the  genera  Anchitherium,  Miohippus,  and  Meso- 
hippus,  with  three  toes  on  each  foot,  and  about  the 
size  of  a  sheep  or  large  goat.  In  the  Eocene  of  Utah 
and  Wyoming  w^e  get  a  step  further  back,  several  spe- 
cies having  been  discovered  about  the  size  of  a  fox, 
with  four  toes  in  front  and  three  behind.  These  form 
the  genus  Orohippus,  and  are  the  oldest  ancestral 
horse  known." 

The  following  account  of  a  horse's  tootlr  that  was 
found  while  digging  a  well  is  from  The  Popular  Science 
Revieiu : 

"In  a  paper  read  before  the  St.  Louis  Academy  of 
Science,  and  reported  in  The  American  Naturalid  for 
March,  1871,  Mr.  G.  C.  Broadhead  records  some  in- 
teresting facts  about  fossil  horses.  Alluding  to  the 
fact  that  horse  remains  have  been  found  in  the  altered 


A  TOOTH  FOUXD   IN   DIGGING   A  WELL.  113 

drift  of  Kansas,  he  says  he  is  now  able  to  announce 
tl]at  similar  remains  have  been  discovered  in  a  well  at 
Papinville,  Bates  County,  Mo.  Mr.  O.  P.  Ohlinger, 
wiiile  digging  a  Avell,  nnearthed  a  tooth  at  a  depth  of 
thirty-one  feet  from  the  surface  \  it  was  resting  in  a 
bed  of  sand  beneath  a  -l-inch  stratum  of  bluish  clay 
and  gravel.  Beneath  the  sand  containing  the  tooth 
was  a  gravel-bed  five  feet  in  thickness.  He  sent  the 
tooth  to  Prof.  Joseph  Leidy,  of  Philadelphia,  who  pro- 
nounced it  to  be  the  last  upper  molar  of  a  horse,  prob- 
ably an  extinct  species." 

In  various  volumes  of  the  "  Proceedings  of  the  Acad- 
emy of  Natural  Sciences  of  Philadelphia,"  accounts  of 
many  other  fossil  horses'  teeth  may  be  found,  of  wiiich 
tlie  following  is  a  specimen  ("  Proceedings,"  &e.,  1871, 
p.  113): 

"Prof.  Joseph  Leidy  exhibited  a  specimen  of  an 
upper  molar  tooth,  which  Mr.  Timothy  Conrad  had 
picked  up  from  a  pile  of  Miocene  marl  at  Greenville, 
Pitt  County,  N".  0.  He  believed,  from  its  size  and  the 
intricacy  in  the  folding  of  the  enamel  of  the  islets  at 
the  middle  of  the  triturating  surface,  that  the  tooth 
belonged  to  the  Post- Pliocene  Bgmis  mmplicatus,  and 
was  an  accidental  occupant  of  the  Miocene  marl.  It 
might,  however,  belong  to  a  Hipparion  of  the  Miocene 
period,  but  the  imperfection  of  the  specimen  at  its  in- 
ner part  prevented  its  positive  generic  determination." 

The  discoveries  of  horse  remains  since  1880  by  Prof. 
E.  D.  Cope,  one  of  the  editoi^  of  The  American 
Naturalist,  are  of  an  extraordinary  character,  and  an 
interesting  account  of  them  appears  in  the  Appendix 
to  this  work.     Truly  the  Americas  are  rich  in  fossil 


114  BIRDS    WITH  TRUE   TEETH. 

remains,  and  it  is  becoming  a  common  thing  to  hear 
of  the  unearthing  of  mastodons,  elephants,  etc. 

Note. — The  birds  of  tlie  present  epoch  are  eutirely  desti- 
tute of  true  teeth,  and  the  mandibles  have  generally  more  or 
less  trenchant,  unarmed  linear  edges ;  but  sometimes  they  are 
armed  with  processes  of  bone  simulating  teeth,  but  in  no  other 
respect  entitled  to  that  name.  In  former  epochs,  however, 
there  existed  types  actually  provided  with  true  teeth,  having 
all  the  structural  characteristics  of  those  organs,  and  fitting  in 
sockets  in  the  jaws.  These  have  been  combined  by  Marsh 
under  the  general  term  Odontornithes  (toothed  birds).  —  Gill. 

The  teeth  of  Hespcrornis  were  covered  with  smooth  enamel, 
terminating  upward  in  conical  pointed  crowns  and  downward 
in  stout  roots.  The  young  tooth  probably  formed  on  the  inner 
side  of  the  root  of  the  tooth  in  use,  a  pit  for  its  reception  being 
gradually  made  by  absorption.  The  old  tooth,  being  progres- 
sively undermined,  was  finally  expelled  by  its  successor,  the 
number  of  teeth  thus  remaining  unchanged.  The  teeth  were 
implanted  in  a  common  alveolar  groove,  as  in  Ichthyosaurus. 
The  skeleton  measures  about  6  feet  from  the  point  of  the  tail  to 
the  end  of  the  bill.  Hesperornis  regnlU  appears  to  have  had  14 
functional  teeth  in  the  upper  and  33  in  the  lower  jaw. — Marsh. 

A  fossil  is  the  body  or  any  known  part  or  trace  of  an  animal 
or  plant  buried  by  natural  causes  in  the  earth.  The  molds  of 
shells,  the  impressions  left  by  the  feet  of  animals  in  walking, 
implements  of  stone  or  metal,  and  other  works  of  human  art 
which  have  been  accumulated  naturally  into  rubbish-heaps, 
are  thus  strictly  fossils.  Perhaps  the  marks  of  rain,  wind, 
waves,  and  shrinkage  through  heat  should  be  included.  *  -  * 
Fossils  indicate  the  former  existence  of  organic  races  now 
entirely  extinct  ;  that,  as  a  whole,  each  successive  period  con- 
tained more  highly  organized  structures  than  its  predecessor; 
that  tropical  forms  once  flourished  in  the  polar  regions  ;  that 
each  epoch  was  characterized  by  peculiar  groups.  Hence,  for- 
mations are  identified  in  new  countries  by  means  of  fossils. — 
a  H.  mtcTicod:. 

For  interesting  articles  on  Fcssil  Botany,  Fossil  Fishes, 
Fossil  Footprints,  and  Fossil  Forests,  the  reader  is  referred  to 
Johnson's  "'  New  Universal  Cyclopedia,"  vol.  ii,  pp.  231-0. 


CHAPTER    VI. 

DENTAL   CTSTS    AND   SUPERNUMERAKT   TEETH. 

Teeth  growing  in  various  parts  of  the  Body.— Some  Cysts  more 
Prolific  tiian  others,  Producing  a  Second,  if  not  a  Third, 
"  Dentition."— Reports  and  Theories  of  Scientific  Men.— 
Cases  of  Third  Dentition  in  Human  Beings. 

The  development  of  abnormal  teeth  in  different 
parts  of  the  body  (the  human  body  as  well  as  those  of 
the  lower  animals,  particularly  the  horse),  is  not  the 
least  interesting  feature  in  the  study  of  dental  science. 
To  judge  from  the  reports  that  follow,  one  would  think 
tlie  tooUi-substance  m  some  horses  was  an  unknown 
quantity.  It  would  be  interesting  and  useful  to  know 
whether  in  such  cases  the  natural  teeth  are  in  a  per- 
fectly healthy  state,  and  whether  the  temperature  is 
natural,  instead  of  being  increased,  as  during  certain 
periods  of  teething.  While  the  study  of  these  teeth 
may  not  be  of  paramount  importance,  it  serves  to 
further  illustrate  the  physiological  relations  of  the  den- 
tal system,  and  ought  to  assist  the  surgeon  in  more 
correctly  diagnosing  diseases. 

Surgeon  George  Fleming,  of  the  Royal  Engineers, 
contributed  a  valuable  paper  entitled  "Dental  Cysts, 
or  Tooth-Bearing  Tumors,*'  to  "The  Veterinarian"  for 
18T4  (p.  692),  the  substance  of  which  is  as  follows: 

"'In  The  Gazetta  Medico-Veterinaria  of  Milan  for 
1873  (p.  274),  Profs.  Lanzillotti-Buonsanti  and  Gui- 


116  DENTAL  CYSTS. 

seppe  General!,  of  the  Veterinary  School  of  that  city, 
published  a  most  complete  and  interesting  contribu- 
tion to  our  knowledge  of  the  pathology  of  dental  cysts 
in  the  horse,  well  illustrated  with  wood-cuts,  and  in- 
cluding a  full  bibliographical  record  and  synoptical 
table  of  these  morbid  produc Lions.  From  their  re- 
searches it  would  appear  that  dental  cysts  were  first 
described  by  Mage  Grouille,  in  1811.* 

"  These  teeth-bearing  tumors  have  received  different 
names.  Thus  they  have  been  designated  'erratic'  or 
*  misplaced  teeth,'  'dental  neoplasies,'  'odontocysts,' 
'dental  degeneration  of  the  temporal  bone,'  'temporal 
fistula,'  'abnormal  development  of  teeth  in  unusual 
places,'  'auricular  teeth,'  'odontocele,'  and  'dentiger- 
ous  cysts'  or  'teeth  tumors.'  They  may  be  developed 
in  unusual  places,  such  as  the  temporal  region,  the 
frontal  bones,  the  base  of  the  ear,  the  space  between 
the  branches  of  the  lower  jaw,  the  lumbar  region,  the 
testicles,  and  the  ovaries.  Coleman  stands  alone  in  his 
case  of  a  cyst  found  beneath  the  right  kidney,  in  which 
were  two  small  molars  and  an  incisor,  attached  to  a 
bone  that  resembled  a  jaw,  though  the  Milan  profes- 
sors believe  the  teeth  in  this  instance  may  have  been 
developed  in  a  testicle  retained  in  the  abdominal  cav- 
ity. The  most  common  situation  is  undoubtedly  in 
the  temporal  region,  as  in  seventy-five  recorded  cases 
sixty-eight  were  observed  there.  These  cases  all  refer 
to  the  horse.  Berger-Perriere,  however,  found  a  tem- 
porary incisor  in  a  fistulous  Avound  near  the  right  ear 

*  "Nomeution  is  made  of  the  AldnLyevo/ievoi  ei'  toic  yvddotr,  or 
maxillary  exostoses  of  Apsyrtus  ('  Hipp.  Gr.'  p.  64),  who  recom- 
mends that  these  tumors  should  be  carefully  and  completely 
removed,  or  they  wall  return  of  a  larger  size." 

The  reference  note  is  also  Surgeon  Fleming's. 


A  CYST  MISTAKEN   FOR   GLAXDEHS.  117 

of  a  lamb  two  months  and  a  half  old  ('Recueil  de 
Med.  Veterinaire,'  1835,  p.  586). 

'•In  most  instances  only  one  tooth  is  found.  Gnrlt 
was  the  first  to  find,  on  the  ijiastoid  process  of  the 
temporal  bone,  a  mass  of  molar  teeth  fused,  as  it  were, 
tog-ether.  The  tumor  was  three  inches  and  a  half 
high,  and  about  two  in  its  largest  diameter.  The  horse 
had  been  destroyed  for  glanders.  Goubaux  found  two 
at  the  posterior  portion  of  the  sphenoid  bone,  and  Bay 
four.  In  a  cyst  of  the  testicle  Gurlt  discovered  six 
teeth,  three  S3i)arate  and  three  in  a  mass.  Bay  at- 
tended a  horse  in  1800  that  appeared  to  be  suffering 
with  encephalitis.  It  died  twenty-four  hours  after  his 
visit.  It  had  always  shown,  on  the  right  temporal  re- 
gion, a  tumor  without  a  fistula,  but  it  did  not  attract 
notice,  as  it  apparently  caused  no  inconvenience.  Nine 
years  afterward,  when  Bay  was  preparing  the  head  as 
a  pathological  specimen,  he  discovered  this  supposed 
exostosis  to  be  constituted  by  the  union  of  four  molar 
teeth.  The  two  superior  teeth  projected  from  the 
temporal  articulation,  and  the  inferior  two  were  situ- 
ated in  the  petrous  portion  of  the  temporal  bone,  in- 
clining obliquely  from  within  outward.  The  posterior 
portion  of  the  latter  projected  in  a  very  salient  manner 
at  the  seUa  turcica,  and  must  have  produced  much 
pressure  on  important  parts  of  the  brain. 

"  Age  does  not  appear  to  have  any  influence  on  the 
development  of  these  cysts,  the  animals  in  which  they 
have  been  observed  ranging  in  age  from  eight  or  nine 
months  to  fifteen  years.  The  period  of  formation  also 
varied  greatly.  In  regard  to  the  side  of  the  body  in 
which  they  were  developed,  in  seventeen  cases  they 
w^ere  on  the  left,  and  in  thirteen  on  the  right.  In 
fourteen  cases  observed  by  Macrops,  they  were  indiffer- 


118  DEXTAL  XYSTS. 

ently  on  both  sides.     lu  this  respect  clinical  obsevva- 
tion  has  not  yielded  any  fact  of  practical  importance. 

"Sometimes,  after  the  extraction  of  a  tooth,  it  hap- 
pens that  the  cavity  of  the  cyst  or  the  bottom  of  the 
fistula  does  not  cicatrize.  This  is  a  sure  indication 
that  a  new  tooth  is  forming.  Rodet  noted  this  fact  as 
long  ago  as  1827.  Macrops  has  observed  a  case  of  this 
kind.  He  was  compelled  to  operate  twice  within  three 
months,  each  time  removing  a  molar  tooth;  and  when 
he  made  his  report,  in  1860,  it  was  probable  that  a 
third  tooth  was  being  developed,  as  the  fistula  had  not 
closed." 

Surgeon  Fleming  also  mentions  cases  that  were  ob- 
served by  Surgeons  Perosino,  Martin,  Harold,  Gamgee, 
Coclet,  Lafosse,  and  others.     He  continues: 

"Profs.  Lanzillotti-Buonsanti  and  Generali  made 
minute  inspection  of  a  specimen  of  tooth  taken  from 
the  bas3  of  the  ear  of  a  foal  twenty  months  old,  and 
they  report  that  microscopically  the  structure  of  such 
teeth  does  not  differ  much  from  natural  teeth.  The 
same  constituents — dentine,  enamel,  and  cement — 
were  found,  the  only  difference  being  that  they  were 
arranged  in  an  unusual  manner.  In  the  tooth  they 
examined,  for  instance,  the  cement  was  abundant  in 
the  central  part,  while  in  that  studied  by  Oreste  and, 
Falcanlo,  the  dentine  was  most  abundant  and  the 
cement  least  in  quantity." 

Surgeon  Fleming  next  refers  to  and  gives  a  sum- 
mary of  t!ie  views  of  scientific  men,  who  say  that  "A 
certain  number  of  teeth  may  sometimes  be  developed 
as  parasitic  productions  in  a  cavity  similar  to  and  situ- 
ated near  the  mouth  (in  which  category  is  included 


A  FETUS  WITIII:N'  A  FETUS.  119 

the  excellent  case  occumug  in  a  woman,  and  da- 
scribed,  in  1862,  by  Prof.  Generali — an  observation 
unique  in  the  teratology  of  mankind — namely,  a 
case  of  parasitic  monstrosity,  in  whicii,  however,  the 
designation  'dental  cyst,'  so  inexact  in  itself,  is  in- 
appropriate and  false);"  that  "the  ovarian  cysts  in 
women,  in  which  have  been  found  pieces  of  bone  and 
cartilage,  teeth,  and  a  lower  jaw,  more  or  less  de- 
formed, ought  to  be  considered  as  probable  cases  of 
ovarian  impregnation  with  an  incompletely  developed 
fetus,  and  in  young  girls  as  examples  of  the  intra- 
uterine formation  of  a  fetus  wnthin  a  fetus;"  that 
"only  in  this  way  can  be  explained  the  lipomatous 
and  sarcomatous  congenital  masses  contained  in  cysts, 
with  the  teeth  and  fragments  of  bone  simulating  an 
incomjdete  jaw,  which  have  been  observed  on  tlie 
human  orbit  (Lobstein  and  Travers),  on  the  palate 
(Otto),  on  the  tong'ue  (Stansky),  on  the  side  of  the 
jaw,  in  the  cheek,  and  on  the  neck,  but  which  Scliultze 
and  Panum  consider  as  the  simple  proliferation  of  em- 
bryonic plasmatic  cells;"  that  "some  dental  cysts  are 
true  dermoid  cysts,  containing  hair  and  teeth,"  &c., 
and  closes  his  paper  w^ith  the  following  common-sense 
suggestion : 

"  Perhaps  direct  researches,  which  have  not  yet  been 
made,  carried  out  in  favorable  circumstances,  will  bet- 
ter serve  in  deciding  their  real  nature  than  all  the 
more  or  less  brilliant  academical  reasoning." 

John  Gamgee,  Professor  of  Anatomy  and  Physiology 
in  the  Edinburgh  Veterinary  College,  in  the  course  of 
a  seiies  of  articles  on  various  subjects  in  "The  Veter- 
inarian" for  1856,  thus  comments  on  a  case  of  dentig- 
erous  cyst,  the  history  of  which  was  originally  written 


120  DEXTAL   CYSTS. 

by  Monsieur  Lafosse  and  published  in  the  ^^  Journal 
des  Veterinaire  da  Midi:" 

"  M.  Lafosse,  Professor  of  Clinical  Medicine  in  the 
Veterinary  School  of  Toulouse,  had  under  his  treat- 
ment a  four-year-old  maro  that  for  two  months  before 
admission  into  the  iniirmary  was  affected  with  a  phleg- 
monous tumor  in  the  reo'ion  of  the  left  ear.  This  was 
opened.  The  wound  that  resulted  rapidly  contracted, 
but  a  fistula  remained.  When  Lafosse  first  saw  the 
case,  he  found  a  painful  tumor,  with  a  granulating 
"wound  just  behind  the  scutiform  cartilage,  and  near 
the  upper  part  of  the  parotid  gland.  By  probing  he 
ascertained  that  at  the  bottom  of  the  fistulous  tract 
w::s  some  hard  substance,  which  he  supposed  to  be  the 
scutiform  cartilage  in  an  ossified  state,  or  a  portion  of 
the  temporal  bone  exfoliating.  A  severe  operation 
was  performed,  and  the  solid  substance  extracted.  It 
w^as  double,  deeply  seated,  and  firmly  adherent  to  sur- 
rounding textures.  Slight  hemorrhage  ensued  from 
the  division  of  the  anterior  auricular,  but  was  easily 
stopped.  The  wound  was  dressed,  and  the  animal 
soon  recovered,  having  shown  only  a  few  symptoms  of 
sore  throat  after  the  operation. 

"I  shall  not  translate  M.  Lafosso's  description  of 
the  products  he  extracted.  They  were  composed  of 
tooth-substance,  and  although  it  has  been  questioned 
whether  it  is  real  tooth  that  is  developed  in  the  shape 
of  accidental  growths  in  the  region  of  the  ear,  still  the 
fact  is  now  well  established,  however  puzzling  to  the 
minds  of  some  it  may  be  to  compreliend  their  origin. 

"  Lafosse  attempts  a  teratological  explanation,  but 
asks:  'If  teeth  arc  looked  on  as  arising  from  the  tcgu- 
mentary  system,  considering  them  in  most  animals  as 


TEETH  EMA^^ATIXG   FROM   OSSEOUS   SYSTEil.     131 

emanating  from  papillse  and  mucous  membrane^  where 
was  the  darmoid  papilla  that  constituted  the  basis  of 
development  of  this  tooth,  deeply  seated  and  close  to 
the  ear,  especially  as  what  might  be  taken  as  the 
crown  looked  toward  the  inner  surface  of  the  skin?' 

"  Further  on  Lafosso  shows  that  in  certain  animals 
teeth  absolutely  emanate  from  the  osseous  system,  as 
in  the  coluber  scaber  and  other  serpents,  in  which  true 
osseous  eminences,  coated  by  enamel,  pierce  the  esoph- 
agean  tunics,  and  project  into  the  tube ;  they  are  at- 
tached to  about  thirty  vertebrae,  of  vv^liich  they  form 
the  inferior  spinous  process.  These  are  intended  to 
crush  the  eggs  that  the  serpents  feed  upon. 

''  Having  established  the  fact  tliat  teeth  may  spring 
from  bone  as  well  as  mucous  membrane,  Lafosse  leads 
us,  where  we  never  suspected,  to  consider  the  dental 
tumors  above  spoken  of  as  congenital,  and  he  looks 
on  them  as  having  sprung  from  some  rudiment  of  a 
maxillary  bone.  In  a  word,  he  looks  on  the  abnormal 
tooth  in  question— without  offering  any  plausible  ex- 
planation—as an  aberration  in  development.  He  does 
not  class  such  teeth  Avith  the  teeth  formed  in  the 
ovary,  &c,,  but  rather  with  those  instances  where  an 
extra  limb  or  portion  of  an  extremity  is  to  be  met  with. 
It  is  an  accidental  excess  of  parts  in  an  otherwise  well- 
formed  body.  'It  cannot,'  says  Lafosse,  'be  looked  on 
as  an  osseous  transformation  of  certain  tissues.' 

"I  have  spoken  of  the  case  at  length,  for  surgically 
it  is  of  the  very  greatest  interest.  As  pathological 
anatomists,  it  is  our  duty  to  study  the  laws  of  disease 
as  well  as  health.  It  is  praiseworthy  to  dive  into  the 
7nysteries  of  the  origin  of  monsters,  but  it  is  essential 
to^idhere  to  facts  and  not  sacriiico  them  to  theoretical 
explanations. 
6 


122  DEXTAL  CYSTS. 

"  III  common  with  others,  I  have  studied  several  of 
these  dental  tumors.  They  may  spring  from  several 
of  the  bones  of  the  head,  but  especially  from  the  region 
of  the  petrous  temporal  hone.  They  may  project  to- 
ward the  interior  of  the  cranium,  but  they  more  fre- 
quently project  outwardly.  They  may  be  strongly 
implanted  in  the  bone,  or  get  separated;  then  they 
are  maintained  in  their  situation  by  the  soft  textures 
around.  Their  development  is  not  more  extraordinary 
than  that  of  other  osseous  growths  that  spring  from 
the  cranial  or  maxillary  bones ;  and  their  tooth-formed 
structure  (teeth  in  the  region  of  teeth),  is  not  more 
wonderful  than  bony  tumors  in  other  parts  of  the  sys- 
tem, whether  connected  or  not  with  the  skeleton.^' 

Prof.  William  Sew  ell,  President  of  the  British  Vet- 
erinary ]\Iedical  Association,  at  the  meeting  of  that 
body  on  May  15, 1838,  advanced  an  interesting  theory 
of  the  growth  of  abnormal  teeth.  It  may  be  true,  for 
after  the  teeth  have  attained  their  full  groAvth,  it  is 
reasonable  that  the  dental  arteries  are  less  active.  But 
as  the  teeth  continue  to  grow  throughout  life,  a  fact 
Prof.  Sewell  does  not  mention,  it  is  not  so  reasonable 
that  they  even  "in  a  manner  cease"  to  act.  The  pro- 
fessor's remarks  are  thus  reported  ("Veterinarian," 
1838,  "Proceedings  Vet.  Med.  Ass.,"  p.  199): 

"  The  President  begged  leave  to  direct  the  attention 
of  the  meeting  to  a  horse's  tooth  that  had  been  pre- 
sented to  him.  It  was  a  fine  specimen  of  the  anomaly 
occasionally  observed  in  the  dental  system  of  the  horse 
— the  production  of  teeth  in  other  places  than  the 
alveolar  cavities,  after  the  natural  teeth  had  been  per- 
fected. The  situations  which  Xature  in  her  wander- 
ings selected  were  occasionally  very  singular.     He  had 


TEETH  LIKE  A  CALF'S   YOUXG  HORK".  123 

seen  a  tooth  v/hicli  grew  from  the  petrous  portion  of 
the  temporal  bone,  like  a  young  horn  from  the  fore- 
head of  a  calf.  It  formed  a  hard  and  seemingly  very 
painfal  tumor,  which  was  ultimately  opened,  and  the 
bony  substance,  which  proved  to  be  an  almost  perfect 
tooth,  extracted.  He  had  seen  three  or  four  similar 
cases  in  which  teeth  had  been  thus  produced.  When 
the  dental  arteries  in  a  manner  cease  to  act — the  teeth 
having  attained  th.eir  full  growth — there  was  a  singu- 
lar predisposition  in  the  neighboring  arteries  to  take 
on  the  same  action,  and  teeth,  more  or  less  perfect, 
were  formed  in  parts  altogether  unconnected  with  den- 
tition. In  this  case  there  were  two,  one  on  either  side 
of  the  forehead." 

Surgeon  F.  Denenbourg  makes  a  detailed  report  in 
"The  Veterinarian"  for  1869  (p.  533)  of  six  cases  of 
dental  cyst,  five  of  which  he  operated  on  successfully. 
The  first  case  he  treated  was  in  1837.  He  confesses 
that  he  believed  them  to  be  mucous  tumors  till  1851, 
when  he  found  a  molar  tooth  perfectly  farmed.  This 
tooth,  which  was  deposited  in  an  anatomical  museum, 
w^as  as  large  as  a  pigeon's  egg,  and  had  three  roots. 

Surgeon  C.  C.  Grice,  of  New  York,  makes  the  fol- 
lowing report  ("  Veterinarian,"  1867,  p.  392) : 

"  Whether  the  case  the  fticts  of  which  I  am  about  to 
communicate  will  prove  of  sufficient  interest  to  be  pre- 
sented to  the  notice  of  the  veterinary  profession,  or 
will  add  anything  to  the  advancement  of  veterinary 
pathology,  I  know  not ;  yet  I  would  be  glad  to  see  it 
inserted  in  our  respectable  old  journal,  '  The  Veteri- 
narian,' for  I  hold  it  to  be  the  duty  of  every  member 
of  the  profession  to  advance  its  interests  to  the  best  of 


124  DEXTAL  CYSTS. 

his  ability.  I  send  it  because  to  me  it  is  a  very  rare 
case.  I  have  now  been  in  practice  more  than  fort}^ 
years,  and  I  have  not  met  with  anything  of  the  kind 
before. 

'^At  the  reqnest  of  Mr.  Barnum,  a  merchant  of  our 
city  and  the  owner  of  a  breeding-farm  in  Westchester 
County,  I  attended  a  two-year-old  colt,  considered  to 
be  very  valuable,  as  he  comes  from  trotting  stock.  Mr. 
Barnum  merely  said  the  colt  had  a  discharge  from  the 
base  of  the  near  ear,  and  that  it  had  existed  for  ten 
months. 

*•!  found  the  animal  so  very  shy  on  account  of  the 
previous  torturing  of  liis  attendants,  that  I  could  not 
approach  him ;  therefore  I  had  to  cast  him.  The  in- 
troduction of  the  probe  failed  to  satisfy  me  that  any 
foreign  body  existed  there;  but  on  dilating  the  orifice 
and  introducing  the  most  reliable  of  all  probes,  my 
forefinger,  I  discovered  a  hard  substance,  which  was 
firmly  attached  to  the  temporal  bone  and  surrounding 
parts.  I  could  not  grasp  the  substance  with  the  for- 
ceps, therefore  I  used  the  handle  of  the  instrument  as 
a  lever,  and  after  using  great  force  dislodged  it.  Mr. 
B:irnum  picked  up  something  in  the  grass  four  or  five 
yards  from  me,  and  it  proved  to  be  a  molar  tooth.  On 
examining  the  wound  afterward  I  found  some  loose 
fragments  of  bone,  and  on  removing  them  they  ap- 
peared to  be  the  socket  of  the  tooth. 

"1  would  have  sent  you  a  report  of  this  case  earlier, 
but  I  was  desirous  of  seeing  its  termination.  Mr.  Bar- 
num says  the  parts  have  entirely  healed  and  left  no 
blemish." 

Prof.  William  Williams  advances  an  interesting  the- 
ory regarding  the  cause  of  dental  cysts  and  also  the 


AMAUROSIS  AXD   ATROPHY  OF  THE  EYES.         1;>5 

manner  of  their  formation.     He  says  ("  Principles  and 
Practice  of  Veterinary  Surgery,"  p.  412) : 

^•'  Cysts  containing  teeth  have  been  found  in  the  tes- 
ticles and  other  parts  of  the  body,  but  those  which  are 
of  importance  to  practical  men  are  found  within  the 
antrum.  I  have  seen  several  cases  of  this  kind,  and 
have  extracted  teeth  from  cysts  even  so  high  as  the 
base  of  the  ear. 

^'During  hfe  these  tumors  are  distinguishable  by 
more  or  less  disfigurement  of  the  face,  by  a  bulging  out 
of  the  superior  maxillary  bone,  accompanied  in  some 
cases  by  amaurosis  of  one  eye,  succeeded  by  atrophy 
of  the  eye  from  the  pressure  of  the  growing-  tumor. 
In  other  cases  these  complications  are  not  present,  but 
now  and  then  an  abscess  forms  in  the  post-orbital  re- 
gion, which  will  be  found  on  examination  to  contain  a 
hard  body — an  imperfect  tooth. 

"  To  understand  the  process  by  which  these  tumors 
are  formed,  it  is  necessary  to  remember  that  the  teeth 
of  all  animals  belong  to  and  arise  from  the  membran- 
ous portion  of  the  digestive  canal,  and  that  at  a  very 
early  period  of  fetal  life  a  provision  is  made  for  the 
development  of  the  permanent  teeth  as  well  as  the 
temporary.  This  provision,  according  to  Goodsir,  is 
as  follows :  '  As  early  as  the  sixth  week  of  intra-uteral 
life  (human),  a  groove  appears  along  the  border  of  the 
future  jaws,  called  the  primitive  dental  groove,  which 
is  lined  by  the  membrane  of  the  mouth.  At  the  bot- 
tom of  this  groove  projections— papillae — spring  up, 
corresponding  in  number  with  the  temporary  teeth. 
While  the  growth  of  the  papillae  is  going  on,  partitions 
are  formed  across  the  grooves,  by  which  they  become 
separated  from  each  other.      These  partitions  subse- 


126  DEXTAL  CYSTS. 

quently  form  the  bony  sockets^  thus  placing  each 
papilla  in  a  separate  cavity.  Concurrent  with  this 
process,  small  growths  take  place  upon  the  membrane 
of  the  month,  just  as  they  dip  into  the  papillary  cavity 
or  follicle,  which  finally,  by  union  with  other  growths, 
form  a  lid  which  covers  the  papillae  in  a  closed  sac  or 
bag.  Before  the  final  closing  of  the  follicle,  a  shght 
folding  inward  of  its  lining  membrane  takes  place. 
This  inward  folding  of  the  membrane  of  the  primitive 
groove  is  for  the  purpose  of  forming  a  new  cavity — the 
cavity  of  reserve — which  furnishes  a  delicate  mucous 
membrane  for  the  future  formation  of  the  permanent 
teeth.  The  cavity  in  which  the  permanent  tooth  is 
developed  is  a  mere  detachment  from  the  lining  of  the 
primitive  groove,  and  in  it  a  papilla  is  formed  in  the 
same  w^ay  as  that  of  a  temporary  tooth.'  * 

"  Now,  I  look  on  the  formation  of  these  tumors  as 
being  due  to  some  irregularity  in  this  folding  of  the 
lining  membrane,  by  which  the  'cavity  of  reserve'  is 
made  up  of  several  folds ;  that  these  folds  eventually 
become  separated,  forming  separate  cavities  of  reserve, 
and  that  a  papilla  similar  to  those  of  the  natural  teeth 
is  developed  in  each  cavity.  These  irregular  papillae 
are  converted  into  irregular  teeth,  which,  for  want  of 
space  in  the  mouth,  are  forced  into  the  antrum,  and 
may  completely  block  it  up,  as  well  as  the  posterior 
nasal  opening. 

"  I  have  classified  them  as  cystic  tumors,  as  at  first 
they  are  inclosed  in  sacs  or  cysts.  They  soon  burst 
through  their  investing  membrane,  however,  and  form 
a  large  tumor,  composed  entirely  of  teeth,  having  a 

*  Compare  Professor  Gondsir's  theory  with  tliose  advanced 
by  Messrs.  Owen,  Tomes,  Chauveau,  and  others  in  the  first 
chapter. 


A  BULL  WITH   AX   UPPER  INCISOE.  127 

great  variety  of  shapes,  and  riuiiiing  in  different  direc- 
tions. The  teeth  vary  in  size,  some  being  very  small, 
while  others  are  nearly  as  large  as  a  permanent  grinder. 
Each  tooth  has  a  pulp  cavity,  and  is  composed  of  the 
Sam3  snbstances  as  the  natural  teeth.  Should  their 
removal  be  desirable,  it  will  be  necessary  to  trephine 
the  superior  maxillary  sinus  and  detach  them  with  the 
forceps." 

In  the  chapter  entitled  "The  Pathology  of  the 
Teeth"  (the  VIII.),  Surgeons  Bouley  and  Ferguson, 
in  the  course  of  their  memoir  on  horses'  teeth,  record 
some  important  facts  about  supernumerary  teeth.  In 
one  animal  the  rows  of  grinders  are  said  to  appear 
double.  The  facts  are  given  in  that  particular  chap- 
ter in  preference  to  the  present  one  in  order  that  the 
memoir  may  have  a  connected  reading. 

M.  Koche  Lubin  gives  the  following  accoant  of  a 
tooth  that  he  extracted  from  the  upper  jaw  of  a  young 
bull  ("Le  Zooiatre  du  Midi,"  February,  1838): 

"  On  the  lltli  of  April,  1837,  I  was  requested  by  M. 
Bonhome,  who  lives  near  Rhodez,  to  extract  a  tooth 
which  was  growing  in  the  middle  of  the  palate  of  his 
young  bull.  The  novelty  of  the  thing  made  me  hasten 
to  comply  with  his  request.  The  animal  being  secured, 
I  removed  the  tooth  in  the  usual  way.  A  ver^  consid- 
erable hemorrhage  followed  its  extraction,  which  was 
13erformed  with  some  difficulty  on  account  of  the  tooth 
being  firmly  implanted  in  the  palatine  arch.  It  was 
situated  at  the  middle  of  the  median  line,  and  was  of 
precisely  the  same  character  as  tliat  of  the  usual  incisor 
tooth  of  the  ox.  This  is,  I  believe,  the  only  case  on 
record,  the  incisor  teeth  being  wanting  in  the  upper 
jaw  of  cattle." 


128  SUPERNUMERARY   TEETH. 

Human  beings,  like  the  lower  animals,  are  now  and 
then  afflicted  with  a  superfluity  of  tooth-substance,  or 
at  least  they  have  supernumerary  teeth.  John  Hunter 
says  {''  The  Human  Teeth/'  p.  53) : 

"We  often  meet  with  supernumerary  teeth,  and  this, 
as  well  as  some  other  variations,  happens  oftener  in 
the  upper  than  in  the  lower  jaw,  and,  I  believe,  always 
in  the  incisors  and  cuspidati.  I  have  only  met  Avith 
one  case  of  this  kind,  and  it  was  in  the  upper  jaw  of  a 
child  about  nine  months  old.  The  bodies  of  two 
teeth,  in  shape  like  the  cuspidati,  were  placed  directly 
behind  the  bodies  of  the  two  first  permanent  incisors; 
so  that  there  were  three  teeth  in  a  row,  placed  behind 
one  another,  namely,  the  temporary  incisor,  the  body 
of  the  permanent  incisor,  and  that  supernumerary 
tooth.  The  most  remarkable  circumstance  was  that 
these  teeth  v/ere  inverted,  their  points  being  turned 
upward  and  bent,  caused  by  the  bone  which  was  above 
them  not  giving  way  to  their  growth,  as  the  alveolar 
process  does." 

The  following  account  of  cases  of  third  dentition  in 
human  beings  is  from  "Bond's  Dental  Medicine" 
(p.  210): 

'■'Third  Dentition. — A  number  of  well  authenticated 
cases  of  partial  and  even  complete  dentition,  occurring 
in  very  old  persons,  are  recorded  in  the  books.  In  one 
instance,  given  in  the  'Edinburgh  Medical  Com.'  (vol. 
iii.),  the  patient,  who  was  sixty  years  old  and  entirely 
toothless,  suffered  very  severely.  At  the  end  of  twenty- 
one  days  from  the  beginning  of  his  sufferings,  however, 
he  was  compensated  by  the  appearance  of  a  complete 
set  of  new  teeth. 


THIRD   DEXTITIOXS    FATAL.  129 

"With  regard  to  the  constitutional  effects  of  this 
abnormal  dentition,  Prof.  Harris,  who  relates  two 
cases  as  having  occurred  under  his  own  observation, 
says :  'It  seems  tliat  the  efforts  made  by  nature  for  the 
production  of  a  third  complete  set  of  teeth  are  usually 
so  great  that  they  exhaust  the  remaining  energies  of 
the  system,  for  occurrences  of  this  kind  are  generally 
soon  followed  by  death.' " 

Eetextion  of  Deciduous  Teeth.— Miss  A.  B., 

aged  twenty  years,  has  never  shed  her  deciduous 
second  molars.  They  are  sound  and  healthy,  except 
one.  The  first  bicuspids  have  been  erupted;  the 
second  have  not.  Would  it  be  proper  to  extract  the 
temporary  teeth? — M.  A. 

In  answer  to  M.  A.,  in  the  November,  1881,  num- 
ber of  the  Dental  Cosmos,  I  would  reply  that  from 
my  experience  it  would  be  poor  practice  to  extract 
healthy  deciduous  molars  at  that  age,  merely  because 
they  were  deciduous,  and  when  nothing  else  indicated 
such  treatment.  I  have  met  with  many  such  cases. 
Sometimes  only  one  or  two  of  the  molars  are  retained  ; 
at  other  times  three  or  four.  I  know  of  two  sisters, 
over  forty  years  of  age,  who  have  each  their  four 
deciduous  second  molars,  and  every  one  perfectly 
healthy. — Stormont. 


CHAPTER    VII. 

HORSES'   TEETH   UXDER  THE   MICROSCOPE. 

The  Dentinal  Tubes,  Enamel  Fibers,  and  Cemental  Canals  De- 
scribed and  Contrasted. 

Prof.  Richard  Owen's  description  of  the  micro- 
scopical appearance  of  horses'  teetli,  like  the  extracts 
already  made  from  liis  works,  is  both  interesting  and 
profound.  The  teeth  described  are  illustrated  in  the 
second  volume  of  the  "  Odontography,"  the  section  of 
the  molar  being  magnified  three  hundred  linear  diam- 
eters; that  of  the  incisor,  however,  is  not  magnified. 
In  the  first  volume  (pp.  576-7-8)  Prof.  Owen  says: 

"  The  body  of  the  long  molar  teeth  of  the  horse 
consists  of  columns  of  fine-tubed,  unvascular  dentine, 
coated  by  enamel,  which  descends  in  deep  folds  into 
the  substance  of  the  teeth.  The  enamel  is  covered 
by  cement,  thickest  in  the  interspaces  of  the  inflected 
enamel-folds  and  upon  the  crowns  of  the  molars,  where 
it  is  permeated  by  vascular  canals,  thinnest  on  the 
crowns  of  the  canines  and  incisors.  At  the  roots  of 
these  teeth,  and  on  those  developed  from  the  w^orn- 
down  molars,  the  dentine  is  immediately  invested  by 
cement. 

"  In  a  vertical  section  of  the  incisor,  as  in  Plate  136, 
Fig.  11,  the  pulp-cavity,  contracting  as  it  approaches 


TUBES   DICHOTOMOUSLY   Br.AXCIIED.  131 

the  vertical  enamel-fold,  divides  near  the  end  of  tliat 
fold,  and  extends  a  little  way  between  it   and  the 
periphery  of  the  incisor,  or  leaves  a  fe\v  uiednllary 
canals  and  a  modified  thin  tract  of  irregularly  formed 
dentine  between  the  reflected  and  the  outer  coat  of 
enamel,  but  rather  nearer  the  former.     Above  this 
tract,  near  the  summit  of  the  crown,  the  dentinal  tubes 
proceed  in  a  nearly  vertical  direction,  with  a  gentle 
sigmoid  primary  flexure,  where  they  diverge  from  the 
perpendicular.     Lower  down  they  diverge  in  opposite 
directions,  curving  from   the   remains  of  the  pulp- 
fissure  toward  the  outer  and  the  inner  enamel,  and  are 
described  by  Retzius  as  being  in  the  form  of  the  Greek 
e;   but  the  course  of  two  distinct  series  of  dentinal 
tubes,  and  not  of  a  single  tube,  is  illustrated  by  this 
comparison.     When  the  pulp-cavity  comes  single  and 
central,  as  at  the  lower  half  of  the  tooth,  the  tubea 
diverge  to  the  periphery,  with  one  principal  primary 
curve,  convex  toward  the  crown.     Each  tube  is  bent 
in  minute  secondary  gyrations  to  within  a  short  dis- 
tance of  its  peripheral  termination,  where  it  is  much 
diminished  in  size,  and  is  dichotomously  branched. 
The  tubes  at  their  beginning  form  the  upper  calcified 
tracts  of  the  pulp-cavity,  which  usually  retain  some 
remnants  of  that  vascular  receptacle  in  the  form  of 
medullary  canals,  and  are   strongly  and  irregularly 
flexuous  before  they  fall  into  the  ordinary  primary 
curves.     These  tubes,  proceeding  tow^ard  the  inner 
reflected  folds  of  enamel,  are  more  vertical  than  the 
tubes  going  to  the  periphery. 

"A  transverse  section  of  the  incisor  of  a  young  horse 
or  ass,  taken  across  the  part  marked  a  in  Fig.  H,  shows 
a  long  oval  island  of  vascular  cement  in  the  center, 
bounded  by  a  border  of  enamel,  with  an  irresfular  ere- 


132        HORSES'  TEETH  UX0ER  THE   MICROSCOPE. 

nate  edge  next  the  cement,  and  an  even  edge  next  the 
dentine,  which  is  here  clearly  seen  to  be  divided  into 
an  inner  and  an  outer  tract  by  an  irregular  series  of 
the  vascular  canals  continued  from  the  summit  of  the 
pulp-cavic}',  and  by  the  irregularly  tortuous  dentinal 
tubes,  which,  with  the  canals,  indicate  the  last  con 
verted  remnant  of  the  pulp  in  this  part  of  the  crown. 
The  inner  tract  of  dentine  next  the  island  of  enamel 
is  well  defined,  and  a  little  broader  than  tlie  secretion 
of  the  enamel  itself,  and  shows  the  extremities  of  the 
tubes  cut  transversely,  which,  as  before  observed,  were 
at  this  point  directed  chiefly  in  the  axis  of  the  incisor 
toward  the  working  surface  of  the  crown.  The  tubes 
in  the  outer  tract  of  dentine,  inclining  more  toward 
the  sides  of  the  tooth,  are  more  obliquely  divided,  and 
at  the  ends  of  the  section  they  are  seen  lengthwise,  ele- 
gantly diverging  toward  the  sides  of  the  section:  This 
tract  of  dentine  is  bounded  externally  by  a  layer  of 
enamel,  one-sixth  part  thicker  than  that  forming  the 
central  island;  and  the  enamel  is  coated  by  an  outer 
layer  of  cement,  of  its  own  thickness  at  the  sides,  but 
thinning  off  at  the  two  ends  of  the  section.  The  den- 
tinal tubes  proceeding  from  the  residuary  pulp-tract 
make  strong  and  irregular  curvatures,  diverging  to 
incluiie  the  divided  areas  of  the  vascular  canals,  and 
in  the  outer  layer,  at  one  side  of  the  section,  they  de- 
scribe strong  zigzag  curves  at  the  middle  ofthe  outer 
division  of  the  dentine. 

"The  diameter  of  the  dentinal  tubes  at  their  central 
and  larger  ends  is  pretty  regular,  about  go^opth  of  an 
inch ;  at  the  middle  of  their  course,  -g-oV^^h  of  an  inch, 
thence  decreasing,  and  very  rapidly,  after  the  terminal 
bifurcations  begin.  The  tubes  are  separated  from  one 
another  by  intervals  varying  between  once  and  twice 


THE  CURVES  OF  THE  DEXTIKAL  TUBES.    133 

their  thickness.  In  some  parts  of  the  dentine  of  the 
incisor  they  are  more  closely  crowded  together,  espe- 
cially near  their  origin  from  the  pulp-cavity.  Their 
secondary  gyrations  describe  a  curve  of  about  y^Voth 
of  an  inch  in  length.  These  subside  in  the  slender 
terminations  of  the  tubes,  which  bifurcate  dichoto- 
mously  once  or  twice,  and  send  off  small  lateral 
branches  near  the  enamel.  The  small  lateral  branches 
are  chiefly  visible  in  the  peripheral  third  part  of  the 
tubes,  and  are  sent  off  at  very  acute  angles,  except  in 
the  strongly  and  irregularly  bent  origins  from  the 
pulp-tract.  I  have  never  seen  these  small  branches  of 
the  dentinal  tubes  terminating  in  radiated  cells,  like 
those  of  cement  and  bone,  as  Retzius  describes;  but 
the  peripheral  smallest  branches  near  the  enamel  occa- 
sionally dilate  into  corpuscles  much  more  minute 
than  the  radiated  cells,  as  they  do  in  the  teeth  of  most 
quadrupeds. 

"  The  dentine,  as  seen  in  a  longitudinal  section  of 
the  crown  of  a  molar,  by  a  magnifying  power  of  three 
hundred  hnear  dimensions,  is  figured  at  a,  Plate  137. 
The  tnbes  are  here  separated  by  rather  wider  inter- 
spaces than  those  of  the  incisor,  and  do  not  decrease 
in  size  so  rapidly.  The  convexity  of  the  terminal  bend 
of  the  tubes  is  turned  toward  the  summit  of  the  crown. 
In  the  incisor,  the  clear  dentinal  cells  are  very  small 
near  the  peripheral  part  of  th«  dentine,  but  increase  in 
size  as  they  approach  the  pulp-cavity.  They  are  of  a 
sub-circular  figure,  with  bright,  transparent  lines. 

"The  central  cement  in  the  crown  of  the  incisor  is 
permeated  by  vascular  canals,  separated  by  intervals  of 
from  two  to  three  times  their  own  diameter,  directed 
in  the  middle  of  the  substance  in  the  axis  of  the  tooth, 
but  diverging  like  rays  obliquely  toward  its  periphery. 


134     horses'  teeth  uxder  the  microscope. 

The  clear  substance  forming  the  walls  of  the  canals  is 
arranged  in  concentric  layers,  the  thickness  of  the 
walls  being  about  equal  or  rather  less  than  the  area  of 
the  canal.  The  radiated  cells,  generall}-  of  a  full  oval, 
sometimes  of  an  angular  form,  are  chiefly  dispersed  in 
the  interspaces  of  the  vascular  canals,  and  with  their 
long  axis  parallel  with  the  plane  of  the  layers  of  the 
coats.  The  finer  system  of  tubes  radiating  from  the 
cells,  and  corresponding  by  minute  branches  from  the 
vascular  canals,  freely  intercommunicate.  In  the 
peripheral  cement  of  the  incisors  examined  by  me,  I 
found  no  vascular  canals,  but  only  the  radiated  cells, 
and  the  fine  tubuli  which  I  have  called  'cemental,' 
and  which  traverse  the  cement  at  right  angles  to  its 
plane,  and  communicate  with  the  tubes  radiating  from 
the  cells.  These  are  more  usually  elliptical  than  in 
the  thicker  central  cement,  their  long  axis  being  par- 
allel with  the  borders  of  the  cement.  They  are  most 
abundant  next  the  enamel,  and  rarely  encroach  upon 
the  clear  peripheral  border  of  the  cement.  The  exte- 
rior coronal  cement  of  the  molars  (Plate  137,  c),  is  as 
richly  permeated  by  vascular  canals  (v  v),  as  is  the 
central  cement  of  the  incisor. 

"The  enamel-fibers  of  the  horse's  incisor  are  very 
slender,  not  exceeding  twice  the  diameter  of  the  denti- 
nal tubes.  They  extend,  with  a  single  sigmoid  curve, 
through  the  entire  thickness  of  the  layer,  contiguous 
fibers  curving  in  opposite  directions.  The  peripheral 
border,  or  that  next  the  cement,  is  everywhere  indented 
wdth  hemispherical  pits  from  ji-Q^h  to  ^ o^o o ^^^  ^^  ^'^^ 
inch  in  diameter,  from  four  to  six  of  the  radiated  cells 
of  the  cement  being  often  clustered  together  in  the 
larger  depressions.  The  inner  or  dentinal  border  is 
nearly  even  and   straight;    here  are  seen  the  short 


CLEARNESS  OF  THE  ENAMEL- FIBERS.  135 

cracks  or  fissures  extending  into  the  enamel.  The 
fibers  are  rather  more  wavy  in  the  thicker  enamel  of 
the  molar  teeth  (Plate  137,  b). 

"It*  the  enamel  is  viewed  in  sulflciently  thin  sec- 
tions it  is  free  from  those  wavy,  dusky  markings  which 
are  produced  by  the  more  tortuous  fibers  of  the  human 
enamel;  and  I  have  been  unable  to  distinguish  any 
transverse  striee  in  the  fine  fibers  of  that  tissue  in  the 
horse.  The  appearance  of  such  is  given  by  thicker 
sections  of  the  enamel-fibers  taken  obliquely  across 
them,  and  is  produced  by  the  cut  ends  of  the  fibers." 


CHAPTER    VIII. 

THE  PATHOLOGY  OP  THE  TEETH. 

Importance  of  the  Subject. — Caries  caused  by  Inflamed  Pulps, 
Blows,  Virus,  and  Morbid  Diathesis — Supernumerary  Teeth 
and  other  Derangements. — Trephining  the  Sinuses. — Gutta 
Perch  a  as  a  Filling. — Cleaning  the  Teeth. — A  Diseased  Fos- 
sil Tooth. 

The  importance  of  the  study  of  the  pathology  of 
the  teeth  is  self-evident,  for  they  not  only  bear  impor- 
tant relations  to  the  general  system,  but,  like  all  other 
parts  of  it,  are  subject  to  disease  and  derangement. 
The  fact  that  disease  of  the  teeth  is  involved  in  more 
or  less  mystery,  is  an  argument  in  favor  of  the  study 
of  the  subject,  for,  to  use  Surgeon  Gamgee's  words, 
it  is  a  "duty  to  study  the  laws  of  disease  as  well  as 
health,"  and  "it  is  praiseworthy  to  dive  into  the  mys- 
teries of  the  origin  of"  diseases  as  well  as  monsters.  It 
is  probably  not  too  much  to  say  that,  to  the  successful 
surgeon,  knowledge  of  the  diseases  and  derangements 
of  the  teeth  is  indispensable. 

In  order  to  facilitate  the  study  of  and  cast  light  on 
the  subject,  I  have  brought  into  juxtaposition,  as  it 
were,  a  summary  of  the  views  of  a  few  able  men  in 
regard  to  the  cause  of  caries,  &c.,  wliich,  better  still,  is 
followed  by  the  reports  of  well-known  surgeons,  who 
give  the  results  of  their  experiences  in  detail. 


DECAY,  EXOSTOSIS,   AXD   ABSCESS.  137 

Dr.  G.  A.  Mills  says  that  when  the  tone  of  a  tooth 
can  )3e  brought  to  the  point  of  resistance  of  the  in- 
flammatory process,  dentists  will  have  gone  a  long 
way  in  providing  against  the  effects  of  caries.  The 
dentine  decays  faster  than  the  enamel. 

Prof.  Owen  says  a  tooth  has  no  inherent  power  of 
reparation ;  that  in  growing  teeth,  with  roots  not  fnilj 
formed,  the  cement  is  so  thin  that  the  Purkinjean 
cells  are  not.  visible.  It  looks  like  a  fine  membrane, 
and  has  been  described  as  the  periosteum*  of  the 
roots.  It  increases  in  thickness  with  the  age  of  tlie 
tooth,  and  is  the  seat  and  origin  of  what  ai'e  called 
exostoses  of  the  roots.  These  growths  are  subject  to 
the  formation  of  abscesses  and  all  morbid  actions  of 
true  bone.     Of  a  diseased  fossil  horse's  tooth  he  says : 

"  But  the  cavity  had  eWdently  been  the  result  of 
some  inflammatory  and  ulcerative  process  in  the  origi- 
nal formative  pulp." 

Dr.  Boon  Hayes  says : 

"I  think  it  would  not  be  difficult  to  prove  that 
caries  of  the  teeth  more  frequently  proceeds  from  in- 
flammation beginning  in  the  pulpal  cavity  than  from 
any  other  cause." 

Dr.  Robley  Dunglison  says : 

"The  most  common  causes  of  caries  are  blows,  the 
action  of  some  virus,  and  morbid  diathesis." 

*  Sarpfeon  John  Hughes  says  :  "  The  periosteum  of  the  teeth 
is  not  supplied  with  blood  in  the  way  the  same  membrane  in 
other  parts  of  the  body  usually  is.  It  is  sap]:»Iied  by  means  of 
vessels  coming  from  the  pulp  of  the  tooth."  If  this  is  true,  then 
it  would  be  easy  for  ioflammation  to  be  conveyed  from  one  to 
the  other. 


138       THE  PATHOLOGY  OF  THE  TEETH. 

"  Odontonecrosis  "  is  defined  by  liim  as  "  dental  gan- 
grene," and  '^  Odontrypy "  as  '•  the  operation  of  perfo- 
rating a  tootli  to  evacuate  the  purulent  matter  con- 
fined in  tlie  cavity  of  the  pulp"  (pulpal  cavity). 

Prof.  William  Percivall,  referring  to  two  diseased 
grinder  teeth  (horses'),  says: 

"  They  seemed  to  have  been  cases  which  had  origi- 
nated in  internal  injury." 

Surgeons  Bouley  and  Ferguson  say: 

"In  explaining  caries  of  the  teeth,  we  cannot  invoke 
the  aid  of  inflammation  and  the  modiiications  which 
it  induces  in  the  tissues  it  attacks;  nor  can  we  say 
that  inflammation  implies  an  active  circulatory  move- 
ment, an  afflux  of  liquid,  an  alteration,  nervous  de- 
rangement, &c." 

Possibly  the  gentlemen  were  not  aware  of  the  in- 
flammation that  Prof.  Owen  says  may  exist  "in  the 
original  formative  pulp,"  and  of  tliat  of  "the  pulpal 
cavity" — the  pulp  in  the  cavity  of  a  full-grown  tooth — 
mentioned  by  Drs.  Hayes  and  Dunglison.  Are  not 
sncli  inflammations  liable  to  be  produced  by  colds  or 
violent  shocks? 

Prof.  George  Varnell,  who  believes  caries  of  the  roots 
of  horses'  teeth  is  usually  caused  by  external  violence, 
says : 

"Inflammation  of  the  alveolo-dental  periosteum 
would  tend  to  this  result  (caries  of  the  roots).  When 
the  nutrition  of  any  part  of  a  tooth  becomes  arrested, 
decay  is  likely  to  folio v/.  When  caries  begins  from 
within,  it  is  due  to  arrestation  of  nutrition,  arising 
perhaps  from  disease  of  only  a  part  of  the  central  pulp 


NATURE   BARRICADING  DISEASE.  139 

of  the  tooth;  if  from  without,  it  will  arise  from  the 
periodontal  membrane  where  it  meets  the  gum." 

Dr.  John  Tomes  thus  describes  the  conservative  ac- 
tion of  nature  (barricading  disease,  as  it  were)  when  a 
tooth  is  affected  with  caries  ("'  Dental  Ph^^siology  and 
Surgery '') : 

"When  a  portion  of  dentine  lias  become  dead,  it  is 
circumscribed  by  the  consolidation  of  the  adjacent  liv- 
ing tissue.  The  tubes,  becoming  filled  up,  are  ren- 
dered solid,  and  the  circulation  is  cut  off  from  the  dead 
mass.  This  consolidation  does  not  go  on  gradually 
from  without  inward,  keeping  in  advance  of  the  decay, 
but  occurs  at  intervals.  It  seems  that  successive  por- 
tions of  dentine  lose  their  vitahty,  and  that  the  contig- 
uous living  portions  become  consolidated." 

Prof.  M.  H.  Bouley  and  Surgeon  P.  B.  Ferguson  are 
the  joint  authors  of  a  memoir  on  horses'  teeth,  which 
fills  thirty  or  more  pages  of  "The  Veterinarian"  for 
1844.  The  substance  of  the  part  which  relates  to  the 
pathology  and  dentistry  of  the  teeth  is  as  follows :  * 

"i.  Anomalies  in  the  Number  of  the  Teeth. — Some- 
times, but  very  rarely,  we  meet  with  supernumerary 
grinders  in  the  horse.  The  anomaly  may  be  caused 
by  the  persistence  of  the  temporary  teeth,  the  develop- 
ment of  abnormal  teeth  on  one  or  both  sides  of  the 
arcades  (rows  of  teeth),  and  the  cutting  of  a  greater 

*  The  phraseology  of  Messrs.  Bouley  and  Ferguson's  memoir 
has  been  more  or  less  changed  and  the  matter  somewhat  con- 
densed and  rearranged.  The  surgeons'  golden  ideas  deserve  to 
be  set  forth  in  clearer  and  more  forcible  language  than  they  re- 
ceive at  their  own  hands,  and  it  is  believed  that  some  improve- 
ment has  been  made. 


140       THE  PATHOLOGY  OF  THE  TEETH. 

number  of  permanent  teeth  than  should  naturally 
exist.  In  the  latter  case  it  is  necessary  to  admit  the 
existence  of  a  greater  number  of  dental  bulbs  than  is 
normal.  We  saw  some  time  ago,  at  the  consultation 
of  the  Veterinary  College  in  Alfort,*  a  horse  which,  to 
use  the  words  of  its  owner,  '  had  a  double  row  of  teeth 
in  the  upper  jaw.' 

"  Sometimes  the  supernumerary  tooth  is  situated  in 
one  or  the  other  jaw,  in  front  of  the  normal  range  of 
grinders,  without  having  a  corresponding  tooth  in  the 
opposite  jaw ;  at  other  times  it  is  situated  either  within 
or  without  the  arcade.  The  latter  anomaly  is  caused 
more  frequently  by  the  deviation  of  a  normal  than  by 
the  addition  of  a  supernumerary  tooth.  In  the  first 
instance  it  is  not  long  before  mastication  is  interfered 
with.  The  tooth,  by  its  growth,  which  is  not  counter- 
acted by  wear,  finally  reaches  the  opposite  jaw,  lacera- 
ting the  mucous  membrane  and  contusing  and  some- 
times fracturing  the  bone  itself.  In  the  second  in- 
stance, the  tooth,  if  within  the  arcade,  is  an  obstacle 
to  the  tongue;  if  without,  to  the  cheek.  Besides  these 
evil  effects,  supernumerary  teeth  cause  irregularity  in 
the  arcades,  and  consequently  prevent  the  exact  appo- 
sition of  the  normal  teeth.  They  interfere  also  with 
the  action  of  the  lower  jaw.  Hence  irregularity  in  the 
friction  and  wear  of  the  teeth  follows,  the  result  being 
that  the  performance  of  the  all-important  function  of 
mastication  is  almost  stopped. 

"^.  Anoftialies  in  the  Form  of  the  Arcades. — The 
upper  rows  of  grinder  teeth  form  two  curves,  opposed 
by  their  concavities,  while  the  lower  rows  form  two 

*  A  city  of  France — Prof.  Boulev's  home.  Surgeon  Ferguson, 
an  Englishman,  was  attached  to  the  Paris  British  Legation. 


DEKAKGEME:efTS  OF  THE  GRIXDEP.S.  141 

nearly  straight  lines,  which  converge  as  they  descend 
toward  the  symphysis  of  the  chm.  These  (the  curves 
and  lines)  may  be,  owing,  in  some  cases,  to  congenital 
conformation,  very  irregular.  Sometimes,  in  fact,  the 
curves  of  the  upper  jaw  are  effaced ;  at  other  times, 
and  most  frequently,  the  lines  of  the  lower  jaw  are 
incurvated  within  the  upper  arcades.  The  deformities 
may  exist  singly  or  together.  The  result  is  that,  in 
the  approach  of  the  jaws,  the  relation  is  not  identically 
established  between  the  surfaces  of  friction,  and  the 
result  of  this,  in  turn,  is  an  irregularity  of  wear  and  an 
abnormal  development  of  the  borders  of  the  tables  (the 
crowns  of  the  teeth),  within  in  the  lower  jaw,  without 
in  the  upper. 

''3.  Exuberance  of  ixirticular  imrts  of  the  Dental 
Apparatus.— {A.)  The  upper  grinders  are  wider  than 
the  lower,  so  that  in  order  to  cause  friction  in  their 
entire  thickness,  a  lateral  movement  of  the  lower  jaw 
is  required.  Sometimes,  perhaps  because  the  move- 
ment is  not  effected  throughout  the  entire  limits  of 
the  segment  of  the  circle,  the  outer  borders  of  the 
upper  teeth  do  not  wear  sufficiently,  and  therefore 
become  elevated  and  sharp.  At  other  times  it  is  the 
inner  borders  of  the  low^er  teeth  that  project.  In 
the  former  case  the  cheeks  suffer;  in  the  latter,  the 
tongue. 

"  In  rare  cases  the  tables,  which  present  a  normal 
inclination  inverse  in  the  two  jaws,  at  length  form 
planes  very  oblique.  The  obliquity  is  sometimes  so 
great  that  the  internal  borders  of  the  lower  teeth  are 
very  elevated,  while  the  external  is  almost  level  with 
the  gums.  The  inverse  effect  manifests  itself  at  the 
uj)per  jaw.  The  consequence  is  that  the  half-masti- 
cated food  slips  into  the  pouch  of  the  cheek. 


142  THE  PATHOLOGY   OF  THE  TEETH. 

"  There  is  in  the  museum  of  the  College  at  Alfort  a 
horse's  head  in  which  this  deformity  may  be  seen  in 
its  greatest  degree.  The  tables  of  the  teeth  at  the  right 
side  form  planes  so  much  inclined  that  they  close 
together  like  the  blades  of  sh.ears.  As  there  was  no 
friction  to  wear  the  teeth  down,  they  grew  to  the  hight 
of  three  inches.  The  fourth  and  fifth  teeth  of  the 
right  side  of  this  rare  anatomical  specimen  are  absent. 
Perhaps  they  were  carious.  The  rarefied  and  spongy 
tissue  of  the  socket-bones  indicate  the  seat  of  an  alter- 
ation— probably  caries — which  was  the  point  of  depar- 
ture of  the  general  tumefaction.  The  last  tooth,  by 
its  oblique  direction  toward  the  empty  sockets,  indi- 
cates that  the  loss  of  the  teeth  occurred  during  the  life 
of  the  animal,  some  time  perhaps  prior  to  its  death. 
The  defect  of  the  right  side  doubtless  forced  the  ani- 
mal to  use  the  left  for  the  purposes  of  mastication.  In 
such  cases  the  teeth  that  do  not  wear  grow  till  they 
reach  their  respective  opposite  jaws,  even  when  those 
at  the  opposite  side  of  the  mouth  are  in  exact  con- 
tact, an  anomaly  never  produced  in  the  normal  state. 
The  function  of  mastication  operates  according  to  the 
obliquity  of  contact,  and  a  parallelism  is  estabhshed 
by  friction  between  the  tables  which  normally  would 
be  superposed. 

"  This  appears  to  us  to  be  the  only  interpretation  of 
the  facts,  and  we  have  observed  two  analogous  exam- 
ples in  hving  horses,  but  we  did  not  think  to  ascertain 
whether  the  deformity  of  an  entire  arcade  was  owing 
to  defect  of  a  grinder  or  to  disease  of  the  bone.  The 
solution  of  the  question  would  be  an  important  acqui- 
sition to  the  science  of  dental  pathology, 

"  (B.)  There  is  another  kind  of  deformity  of  the 
arcades  not  very  uncommon.     The  lower  teeth  wear 


"GUMMIJs"G   IT."  143 

out  more  rapidly  than  the  upper,  the  cause  of  which 
is  perhaps  ov/ing  to  the  superiority  of  the  latter  iu  size 
and  strength.  The  crown  surface  of  the  lower  rows 
is  slightly  concave,  the  upper  rows  slightly  convex. 
The  result  is  that  the  lower  center  teeth  are  sometimes 
worn  to  their  sockets,  w'hich  renders  the  mastication 
of  hard  food  impossihle.  At  first,  however,  there  is 
DO  interference  witii  mastication,  and  it  is  usually  only 
in  old  age  that  the  deformity  reaches  its  worst  stage. 
There  is  no  remedy  for  the  defect,  hid  its  progress 
may  he  retarded  hy  the  use  of  soft  food.  * 

''  (C.)  Lack  of  regularity  in  the  length  of  the  rows 
becomes  the  cause,  in  horses  a  little  advanced  in  age, 
of  a  pecuhar  deformity  in  the  first  upper  and  the  last 
lower  grinders.  Generally  the  upper  range  passes  that 
of  the  lower  hy  some  lines,  the  first  upper  grinder  lap- 
ping over;  but  sometimes  the  case  is  the  reverse,  the 
last  lower  grinder  projecting  beyond  the  last  upper. 
The  projecting  part  of  the  tooth  grows  till  it  reaches 
the  opposite  jaw,  when,  unless  it  is  filed  or  chiseled  off, 
the  most  serious  consequences  will  follow. 

"  ( D.)  When  a  tooth  is  entirely  deficient,  the  oppo- 
site tooth  grows  till  it  fills  the  void  ;  then,  no  remedy 
being  applied,  the  work  of  destruction  begins.  If  a 
tooth  is  only  partly  deficient,  no  matter  whether  it  be 
from  fracture,  caries,  or  arrestation  of  growth,  it  is 
gradually  destroyed  by  the  opposite  tooth.  When  it 
is  the  first  upper  giinder  that  is  deficient,  the  first 
lower  acts  on  the  palatine  vault  like  a  battering-ram. 
*I  have  seen,'  says  Solleysel  (1669),  'a  mule  that  had  a 
lower  grinder  of  extreme  length,  the  upper  tooth  being 
absent.     The  palate  was  pierced  to  the  thickness  of  a 

*  The  italicized  words  are  mine. — G. 


144  THE   PATHOLOGY  OF  THE  TEETH. 

finger,  which  caused  the  animal  great  difficulty  when 
he  drank/ 

-'Ji.  Caries  of  the  Teeih. — The  grinder  teeth  of  horses 
are  more  frequently  affected  with  a  profound  alter- 
ation of  their  substance  than  is  generally  believed. 
The  disease  is  called  Caries ;  it  may  not,  however,  be 
strictly  analogous  to  caries  of  tlie  bones,  for  the  bones 
are  vascular,  while  the  teeth  liave  neither  vessels  nor 
nerves.  Caries  of  the  bones  impHes  an  aotive  labor,  in 
which  the  vascular  apparatus  plays  an  important  part. 
It  is  a  phenomenon  of  interstitial  suppuration,  under 
the  influence  of  the  inflammation  which  has  set  the 
capillary -system  of  the  organ  in  play.  In  explaining 
caries  of  the  teeth,  however,  we  cannot  invoke  the 
aid  of  inflammation  and  the  modifications  it  induces 
in  the  tissues  it  attacks;  nor  can  we  say  that  inflam- 
mation implies  an  active  circulatory  movement,  an 
afflux  of  liquid,  an  alteration,  nervous  derangement, 
&c.  U  the  teeth  are  living,  the  laws  which  govern 
their  vitality  are  entirely  unknown  to  us.*  How,  then, 
penetrate  into  the  secrets  of  the  alterations  which  they 
undergo,  when  the  conditions  of  their  normal  existence 
are  enveloped  in  obscurity?  Neither  is  it  possible  to 
resolve  the  question  as  to  the  essence  of  the  aflcction 
designated  by  the  name  of  caries.  Therefore  we  design 
to  muke  known  only  the  different  modes  of  expression 
relative  to  it. 

"Caries  usually  attacks  the  dentine  of  tlie  crown  of 
the  teeth,  between  two  folds  of  enamel.  The  dentine 
becomes  of  a  brownish  or  blacki.di  color,  and  dissemi- 

*  It  sliould  be  borne  in  mind  that  the  above  views  were  enun- 
ciated more  than  a  third  of  a  century  ago.  The  gentlemen 
probably  say  too  much.  Compare  with  Dr.  Hayes's  views  as 
recorded  on  page  xxii. 


Ei^AMEL  SOPTEXED.  145 

nates  an  offensive  odor  sui  generis,  which  perhaps  is 
as  much  owing  to  the  putrefaction  of  the  saliva  in  the 
cavity  as  to  the  decomposition  of  the  dentine.  The 
decay  progresses  between  the  folds  of  enamel,  and  the 
latter  substance,  notwithstanding  its  great  density, 
takes  on  the  blackish  tint  of  the  dentine  and  becomes 
sufficiently  softened  to  allow  of  its  being  cut  by  a  sharp 
instrument.  Sometimes  even  the  planes  of  the  enamel 
dissolve,  and  then  the  cubic  mass  of  the  tooth  becomes 
so  much  decayed  that  it  resembles  a  deep  cavity,  the 
parietes  of  which  are  formed  by  the  planes  of  enamel 
laid  bare  by  the  caries.  Sometimes  caries  attacks  the 
tooth  on  one  of  its  four  side  surfaces;  at  other  times 
the  root  is  attacked ;  but  wherever  its  primitive  seat 
may  be,  the  blackish  veins  always  extend  into  the  den- 
tine, and  thus  isolate  the  plies  of  enamel. 

"  Carious  teeth  rarely  preserve  either  their  form  or 
volume.  They  become  hypertrophied  at  their  roots, 
but  the  effect  does  not  manifest  itself  until  the  disease 
— having  undermined  all  the  layers  of  dentine  in  its 
course — has  penetrated  the  root.  When  the  caries  has 
penetrated  to  the  socket,  the  alveolo-dental  membrane 
becomes  irritated  by  the  contact  of  deca3^ed  matter, 
increases  its  secretion,  and  deposits  a  thick  layer  of 
osseous  matter  in  the  circumference  of  the  root  of  the 
tooth,  which  concretes  irregularly  upon  the  normal 
layers.  The  deposition  does  not,  however,  always  take 
place  in  the  circumference  of  the  root,  for  in  some 
cases  it  is  only  at  isolated  places  that  the  secretion  of 
the  alveolo-dental  membrane  occurs.  Then  the  root 
presents  a  succession  of  large  osseous  tubercles,  which 
bar  the  tooth  in,  rendering  its  extraction  very  difficult. 
When  the  irritation  has  been  from  the  first  sufficiently 
active  to  cause  suppurative  inflammation,  the  normal 
7 


146       THE  PATHOLOGY  OF  THE  TEETH. 

secrotion  is  suspended,  and  pus  collects  in  the  alveolar 
caviij,  around  the  root,  which  then  ceases  to  augment 
in  volume.  In  the  former  case,  however,  the  root, 
augmented  in  volume,  can  no  longer  be  contained  in 
the  cavity,  the  walls  of  which  are  expanded  by  its 
wedo:e-hke  action,  which  accounts  for  the  extreme 
pain  in  the  adjacent  parts,  and  the  particular  altera- 
tions in  the  osseous  tissues.  The  osseous  tissue  tame- 
lies,  and  suppuration  is  established  in  the  interior  of 
the  socket;  the  aiembrane  is  partly  destroyed,  which 
leaves  the  bone  bare  and  exposed  to  the  maceration 
of  pus  and  the  irritating  contact  of  the  morbid  matter 
that  continually  penetrates  into  tlie  socket  by  the 
dental  fistula;  the  bony  tissue  sphacelates  upon  the 
borders,  where  its  substance  is  the  most  compact,  and 
its  spongy  tissue,  which  forms  the  bottom  of  the  cavity, 
soon  becomes  the  seat  of  an  interstitial  suppuration — 
that  is  to  say,  in  fact,  of  veritable  caries.  The  swell- 
ing may  now  extend  throughout  the  entire  extent  of 
the  maxillary  bone,  and  thus  render  mastication  im- 
possible. 

"  It  may  now  be  seen,  an  alteration  of  this  nature 
being  set  in  action,  how  the  phenomena  of  the  nutri- 
tion of  bone  may  be  modified  in  their  direction  to  the 
point  of  producing  osteosarcoma. 

"  Caries  of  the  roots  of  any  of  the  lower  grinders  may 
be  complicated  with  lesions  of  the  jaw,  for  the  lower 
jaw  is  continuous  in  its  entire  extent.  In  the  upper 
jaw  the  phenomena  are  in  principle  the  same,  but  the 
contiguous  nasal  cavities  and  sinuses  induce  complica- 
tions the  study  of  which  is  important.  It  is  also  im- 
portant to  take  into  consideration  the  position  of  the 
diseased  tooth,  in  order  to  appreciate  tlie  extent  of  the 
lesions  which  a  simple  caries  may  produce. 


COMPLICATIONS  WITH  NERVES,  SINUSES,  ETC.     147 

"The  two  first  upper  grinder  teeth  are  separated 
from  the  nasal  cavities  by  a  thin  bone,  which  is  easily 
eaten  through.  When  caries  attacks  their  roots,  the 
inflammation  extends  itself  to  the  membrane  lining 
these  cavities,  and  a  perforation  of  the  osseous  partition 
may  establish  communication  between  Vae  mouth  and 
the  nose.  Under  the  influence  of  interstitial  suj^pu- 
ration,  the  osseous  membrane  is  destroyed  to  an  enor- 
mous extent.  The  aliments  pass  through  the  dental 
fistula  into  the  nose  and  are  expelled  by  it  along  with 
the  product  of  the  morbid  secretion  of  the  pituitary 
membrane. 

"The  third  grinder  is  situated  near  the  maxillary 
sinuses,  from  Avhich  the  root  is  separated  by  a  thin  dia- 
phragm. It  deserves  to  be  specially  noticed  on  account 
of  an  anatomical  peculiarity,  which  renders  caries  of 
this  tooth  very  much  to  be  dreaded.  We  refer  to  the 
position  of  large  fascia  (bundles)  of  the  superior  maxil- 
lary branch  of  the  fifth  pair  of  nerves,  which  make 
their  exit  upon  the  face  by  the  submaxillary  foramen, 
and  which  are  placed  immediately  over  the  root  of  this 
tooth.  It  is  easy  to  imagine  the  pain  that  may  follow 
nervous  complications  in  caries  of  the  roots  of  the 
third  grinder. 

"The  position  of  the  fourth,  fifth,  and  sixth  grinder 
teeth,  immediately  below  the  vast  maxillary  sinuses, 
from  which  their  roots  are  separated  by  thin  osseous 
partitions,  gives  to  caries  of  these  teeth,  and  to  the 
complications  which  it  induces,  a  special .  character, 
which  demands  that  we  should  speak  of  it  somewhat 
in  detail.  These  teeth  communicate  with  the  sinuses 
as  easily  as  the  first  and  second  do  with  the  nose;  but 
the  case  is  far  worse  for  the  horse,  there  being  so  little 
outlet  for  the  pus. 


148       THE  PATHOLOGY  OP  THE  TEETH. 

"Wlien  the  disease  has  penetrated  the  roots,  and 
has  induced  the  usual  inflammatio.n,  the  thin  parti- 
tions that  separate  them  from  the  sinuses  do  not  resist 
very  long.  Destroyed  by  the  dilatory  effort  of  the 
hypertrophied  root  and  the  influence  of  the  caries,  the 
altered  matters  of  the  mouth  have  free  access  into  the 
sinuses.  Under  tlie  influence  of  their  contact,  the 
membrane  of  the  sinuses  irritates,  vascularizes,  and 
thickens  by  a  serous  infiltration  in  the  early  stage. 
Then,  the  primitive  cause  of  this  modification  contin- 
uing, the  membrane  hypertrophies  somewhat,  and  in 
a  short  time,  owing  to  its  vascular  system  being  richly 
developed  by  inflammation,  large  vegetations  of  the 
nature  of  polypi  are  elevated  upon  it.  These,  on  ac- 
count of  the  incessant  augmentation  of  their  volume, 
fill  the  sinuses  and  cause  a  swelling  of  their  walls. 

"When  the  membrane  of  the  sinuses  has  become 
the  seat  of  an  abnormal  vegetation,  an  abundant  quan- 
tity of  purulent  matter  is  secreted,  the  more  liquid 
part  of  which  drains  out  through  the  conduits  leading 
to  the  nasal  cavities,  while  the  more  concrete  part 
remains  in  the  sinuses.  It  then,  according  as  it  loses 
its  serosity,  undergoes  a  transform. ation,  and  finally 
displays  tlie  aspect  of  cadaveric  grease,  which  it  also 
resembles  in  its  repugnant  odor.  There  is  a  great 
analogy  between  the  disease  that  causes  this  particular 
lesion  and  that  of  glanders. 

'^ Synqotomatology. — The  first  symptom  that  indi- 
cates a  derangement  of  the  dental  apparatus  is  a  diffi- 
culty in  mastication.  The  animal,  excited  by  hunger, 
seizes  the  food  with  avidity.  The  motions  of  the  lower 
jaw,  however,  are  made  with  a  sort  of  hesitation,  and 
often  only  at  one  side.  The  imperfectly  masticated 
hay,  which  on  that  account  will  not  pass  through  the 


HUXGRY,   BUT   UJs'ABLE  TO   EAT.  149 

narrow  pharynx,  is  dropped  into  the  manger  in  the 
form  of  cads  or  flattened  pellets.  The  nose  is  plunged 
into  the  feed,  over  which  the  animal  fumbles  and  nib- 
bles, but  of  which  it  eats  little. 

"The  insufficiency  of  nutrition  soon  produces  a 
baneful  effect  on  the  whole  economy.  The  coat  tar- 
nishes, becoming  dry  and  staring;  the  least  exertion 
makes  the  animal  sweat;  it  is  heedless  of  the  whip; 
the  mucous  membranes  become  discolored  ;  the  pulse 
weakens,  and  cold  infiltrations  sometimes  appear  in 
the  extremities.  To  see  an  animal  thus  suddenly 
transformed,  one  is  apt  to  mistake  the  true  cause  and 
attribute  it  to  the  influence  of  some  grave  organic  dis- 
turbance. 

"  These  symptoms  are  common  to  the  different  dis- 
eases and  derangements  of  the  dental  apparatus,  and 
are  sufficfent  to  lead  to  a  positive  diagnosis.  The 
diagnosis,  however,  can  only  be  precisely  determined 
when  the  mouth  shall  have  been  examined,  for  by  this 
means  we  perceive  the  particukir  signs  of  each  of  the 
alterations  that  opposes  the  function  of  mastication. 
The  mouth  may  be  kept  open  by  a  S2)eculum  oris,  or 
even  by  drawing  out  the  free  portion  of  the  tongue, 
which  should  be  held  by  the  thumb  and  the  third  and 
fourth  fingers,  the  index  being  placed  between  the 
inner  side  of  the  upper  lip  and  tlie  gum,  at  the  space 
between  the  grinders  and  the  tushes,  while  the  other 
hand  is  left  free  to  aid  the  inspection  by  taxis. 

"If  the  derangement  be  tlie  result  of  an  exuberance 
of  a  tooth,  vicious  inclination  or  projections  of  the 
tables,  fractured  teeth,  swollen  sockets,  &c.,  the  sight 
is  ordinarily  sufficient  to  detect  it,  for  the  teeth  are, 
besides,  frequently  soiled  by  the  greenish  remains  of 
food  at  the  affected  part,  and  often  even  the  cheek  is 


150  THE   PATHOLOOY   OF  THE  TEETH. 

filled  witli  an  accumulaHon  of  malgroimd  food.  The 
mouth  should  be  cleaned  with  water,  in  order  that  the 
defect  may  bo  more  plainly  seen ;  if,  however,  on  ac- 
count of  its  being  situated  far  back  in  the  mouth  and 
the  motions  of  the  base  of  the  tongue  from  side  to  side 
interce})ting  the  view,  its  nature  cannot  be  discov- 
ered with  the  eye,  it  will  be  necessary  to  resort  to  the 
sense  of  touch.  The  mouth  being  held  open  by  the 
speculum  oris,  or  some  other  firmly-fixed  apparatus, 
the  fingers  should  be  passed  rapidly  within  and  without 
the  arcades,  but  never  on  them,  because  of  the  danger 
of  having  them  crushed :  whatever  may  be  the  degree 
of  forced  dilatation  of  the  mouth,  there  can  never  be 
much  separation  of  the  jaws  in  the  region  of  the  last 
grinders;  besides  the  animal  can  lessen  it  by  pressure. 

"When  the  buccal  membrane  has  been  excoriated 
by  the  contact  of  irregularly-worn  teeth,  the  gums  in- 
flamed, the  jawbones  contused,  and  the  latter  sphace- 
late or  suppurate,  there  are  some  modifications  of  the 
general  symptoms.  The  animal  loses  its  appetite, 
becomes  dull,  'crest-fallen,'  and  agitated  with  febrile 
disturbance,  however  little  the  heart  of  the  iuflamina- 
tion  may  be  extended.  The  saliva,  wdiich  dribbles 
from  the  mouth,  is  stringy,  and,  wdieu  mixed  with 
pus,  fetid;  the  mouth  is  hot  and  its  membrane  in- 
jected ;  there  is  a  turgescence  of  the  gum  at  the  point 
of  inflammation ;  a  tumefaction  of  the  bene,  with  a 
grayish  tint  at  the  point  where  it  is  denuded  and  about 
to  exfoliate,  or  else  fistulse  abut  into  the  heart  of  the 
suppuration  in  the  spongy  tissue  of  the  jaw. 

"Particular  Symptoms  of  Carles. — Caries  of  the 
grinder  teeth  is  characterized  by  peculiar  symptoms, 
some  of  which  are  common  to  the  teeth  in  general, 
while  others  belong  to  some  grinders  in  particular. 


CARIES   DIFFEREiq^T  IX   DIFFERENT   TEETH.      151 

To  give  precision  to  the  diagnosis,  the  position  of  the 
teeth  should  be  taken  into  consideration.  Besides  the 
symptoms  common  to  all  disorders  of  the  teeth,  caries 
in  general  presents  as  diagnostic  signs — 

"  1.  A  fetor  very  remarkable  and  sid  generis  of  the 
month,  and  of  the  saliva  which  hnmefies  it. 

"2.  Dribbling  of  an  abundant  and  stringy  saliva 
from  the  mouth. 

"  3.  Existence  on  one  of  the  faces  of  the  tooth,  and 
principally  upon  its  crown,  either  of  a  blackish  spot  or 
a  large  cavity  of  the  same  color,  according  to  the  ex- 
tent of  the  disease. 

"  4.  The  extreme  pain  that  the  animal  evinces  when 
the  tooth  is  struck. 

'^If  the  disease  is  of  long  standing,  and  especially  if 
it  has  arisen  from  the  side  of  the  root,  in  addition  to 
the  foregoing  modifications  and  complications,  other 
and  more  special  symptoms  manifest  themselves.  The 
bone  tumefies  and  the  animal  evinces  pain  when  it  is 
pressed  by  the  fiugers ;  the  gums  are  affected  with  tnr- 
gescence,  and  bleed  from  the  least  contact;  all  the 
buccal  mucous  membrane  reflects  a  red  tint,  and  in 
the  meantime  fever  sets  in,  manifesting  itself  by  all 
its  ordinary  and  general  symptoms. 

'' Caries  of  the  first  and  second  upper  grinders  may, 
as  already  explained,  be  complicated  with  lesions  of  the 
nasal  cavities.  Then  the  pituitary  membrane  irritates 
and  secretes  abundant  mucosities,  but  at  one  side  only, 
with  which  the  food  becomes  mixed,  giving  it  a  green 
tint,  but  very  different  from  the  secretions  of  glanders. 
The  case  is  different,  however,  in  the  complications 
induced  by  caries  of  the  last  grinders.     In  fact  there 


152       THE  PATHOLOG.Y  OF  THE  TEETH. 

is  such  a  close  resemblance  between  the  symptomatic 
expressions  of  the  nose  following  caries  of  these  teeth 
and  chronic  glanders,  that  error  and  confusion  are 
common.  It  is  therefore  highly  important  to  distin- 
guish these  diseases,  so  essentially  different  in  their 
causes  and  effects. 

"  When  the  membrane  lining  the  sinnses  has  become 
diseased,  followed  by  the  secretion  of  pus  and  polypus 
growths,  a  jettage  is  established  at  one  side  of  the  nose. 
It  is  white,  lumpy,  and  abundant,  and  is  augmented 
in  quantity  by  exercise.  The  lymphatic  ganglions  be- 
come engorged  and  hard,  but  remain  indolent,  and 
generally  roll  under  the  finger.  The  zygomatic  tables 
of  the  upper  part  of  the  superior  maxillary  and  nasal 
bones  swell  at  the  region  of  the  affected  sinuses,  and 
give  a  dull  sound  to  percussion.* 

*  Prof.  V^arnell  says :  "  I  am  not  aware  that  any  animal  suffers 
from  diseases  of  the  sinuses  of  the  head  to  the  same  extent  as 
the  hors3.  The  sinuses  differ  in  size  in  different  breeds,  and  in 
individual  horses  of  the  same  breed.  I  need  scarcely  point  out 
the  necessity  of  bearing  this  fact  in  mind  in  forming-  diagnoses 
of  obs3iil'e  diseases  in  this  region  of  the  head.  In  certain  cases 
it  is  not  only  important  to  ascertain  whether  the  sinuses  contain 
anything  abnormal,  but  also  the  nature  and  extent  of  the  mor- 
bific matter.  Percussion  with  the  ends  of  the  fingers  is  one 
mode  of  obtaining  this  information.  Both  sides  of  the  head 
should  be  struck,  and  the  sound  produced  in  one  part  compared 
with  that  in  another,  and  with  what  it  is  in  health.  I  woiild 
recommend  students  to  become  familiar  with  these  various 
s:)unds.  They  will  be  found  to  differ,  according  to  the  magni- 
tude of  the  sinuses,  in  the  same  way  that  a  large  empty  cask, 
when  struck,  will  differ  in  sound  from  a  small  one.  It  will  als3 
be  well  to  educate  the  ear  to  the  character  of  the  sounds  pro- 
duced by  percussing  the  sinuses  in  diff3rent]y  formed  heads. 
*  *  ^'  The  sinuses,  strictly  speaking,  are  air  cavities, 
which  communicate  freely  with  each  other,  and  by  means  of  a 


DELICATE   DIAGNOSTIC    SIGNS.  153 

"At  the  first  appearance  of  this  group  of  symptoms 
one  is  apt  to  suspicion  the  existence  of  glanders,  but  a 
careful  examination  will  prove  it  to  be  unfounded.  On 
examining  the  nasa!  cavity,  the  lining  membrane  will 
be  seen  to  be  smocth,  polished,  and  uniformly  rosy, 
with  its  normal  foliicular  openings,  and  on  unfolding 
the  superior  wing  (»f  the  nostril,  the  sahent  border  of 
the  cartilage  presents  a  neat  and  polished  surface,  'with- 
out any  little  pimples  or  morbid  tint.  Now,  we  know 
that  in  glanders,  even  of  the  sinuses,  which  is  often 
unaccompanied  by  cankers  or  other  ulcerations,  it  is 
in  those  places  certain  specific  morbid  signs  may  be 
recognized,  which,  although  very  superficial  and  with 
difficulty  seen  by  the  eye,  are  nevertheless  of  great 
value  in  the  diagnosis.  Such,  for  instance,  are  the 
peculiar  aspect  of  the  salient  border  of  the  wing  of  the 
nostril,  with  its  vivid  red  tint,  the  small  superficial 
erosions  of  the  lining  membrane,  entirely  hidden  under 
the  fold  of  the  cartilage,  and  those  small  granular  pro- 
jections called  tubercles.  In  the  jettage  from  caries 
nothing  of  this  kind  exists.  There  is  a  marked  differ- 
ence in  the  odor  too;  in  caries  the  odor  is  exceedingly 
fetid,  while  in  glanders  it  is  almost  null. 

"If,  after  this  attentive  examination,  the  surgeon  is 
still  in  doubt  as  to  the  specific  nature  of  the  nasal  dis- 


small  opening,  with  the  nasal  passage  also.  This  opening  is 
situated  at  the  snpero-posterior  part  of  the  middle  meatus,  and 
is  guarded  by  an  imperfect  valve,  which,  when  pressed  upon 
from  within,  either  partially  or  wholly  closes  it.  It  may  also 
be  closed  by  the  mucous  membrane  being-  thickened  by  disease. 
Internally  the  sinuses  are  partially  divided  into  compartments 
by  thin  osseous  plates,  and  are  lined  by  a  slightly  vascular  mem- 
brane, which  is  continuous  with  that  of  the  nasal  passage,  but 
is  not  so  thick  nor  so  vascular." 


154       THE  TATnOLOGY  OF  THE  TEETH. 

charge,  it  will  disappear  and  give  place  to  a  true  diag- 
nosis when  he  has  examined  the  mouth  and  has  had 
time  to  weigh  and  compare  all  the  facts  in  connection 
with  the  case. 

''It  is  more  especially  relative  to  diseases  of  the  teeth 
that  is  recognized  the  truth  of  the  old  maxim  in  sur- 
gery, SuUatd  causa,  tolUtur  effectus"  (The  cause  be- 
ing removed,  the  effect  ceases.) 

For  putting  irregular  teeth  in  order,  the  surgeons 
recommend  the  use  of  a  coarse,  six-inch  file,  with  a 
handle  from  twenty  to  twenty-four  inches  long.  How- 
ever, they  say  that  in  their  day  it  was  customary  among 
the  "vulgar"  to  make  the  horse  chew  a  rasp!  The 
process,  which  they  describe,  referring  among  other 
things  to  the  difficulty  of  getting  the  rasp  precisely 
opposite  the  projections,  is  too  slow,  as  they  admit,  to 
be  practicable ;  besides  it  is  about  as  difficult  to  com- 
pel a  horse  to  chew  as  to  compel  him  to  drink. 

For  the  removal  of  supernumerary  grinder  teeth  or 
the  shortening  of  natural  ones  that  have  grown  beyond 
the  level  of  the  other  teeth,  they  recommend  the  use 
of  a  chisel  and  a  hammer;  two  or  three  well-directed 
blows  with  the  latter  are  usually  sufficient  to  cat  the 
largest  tooth  in  two.  The  surgeon  requires  an  assist- 
ant or  "  striker."  In  the  case  of  the  first  grinder,  the 
blows  should  be  light,  otherwise  the  tooth  would  be 
loosened  in  its  socket.  In  the  case  of  the  last  grinder, 
"it  is  necessary  for  the  operator  to  be  perfectly  master 
of  the  chisel  at  the  moment  of  its  being  struck,  for,  in 
escaping,  it  might  strike  against  the  velum  palati  (soft 
palate)  and  cut  it  through." 

In  performing  these  operations  they  prefer  that  the 
horse  should  be  in  a  standing  position,  as  when  in  a 


DKEXCHEJJ    WITH   TOOTII-niAGMEXTS.  155 

lying  position  there  is  danger  of  liis  swallowing  the 
fragaients  of  the  teeth.  If  it  is  necessary,  however,  to 
cast  the  horse,  they  recommend  that  the  head  rest  on 
the  occiput,  the  operators  being  us  expeditious  as  pos- 
sible, to  prevent  the  animal  from  swallowing  the  frag- 
ments. As  the  nose  points  up,  tlie  surgeon  would 
have  to  be  expeditious  indeed  in  order  to  prevent  the 
horse  from  being  drenched,  as  it  were,  with  tooth- 
fragments. 

The  surgeons  next  describe  an  interesting  case  of 
dental  surgery,  in  the  performance  of  which  the  bone- 
forceps  w^ere  used  to  remove  the  tushes.     They  say: 

"It  sometimes  happens  tliat  the  fleshy  and  bony 
structures  of  the  mouth  are  not  well  proportioned,  and 
when  the  animal  is  put  to  work  evil  consequences  re- 
sult, especially  if  the  tongue  is  too  large  for  the  space 
between  the  branches  of  the  jaws.  A  remarkable  case 
of  this  kind  lately  came  under  our  observation  in  a 
horse  owned  by  the  Earl  of  Clonmel.  The  animal,  a 
remarkably  fine  one,  was  a  very  hard  'puller,'  in  conse- 
quence of  the  bit  not  coming  in  sufficient  contact  with 
the  sensitive  bars.  The  space  between  the  tushes  was 
too  narrow  for  the  tongue,  w^hich,  after  the  animal  had 
been  ridden  with  restraint  by  a  horse-breaker,  was  cut 
nearly  through  at  each  side.  The  consequence  was  the 
tongue  became  swollen  to  an  enormous  extent,  and 
as  the  tushes  increased  the  irritation,  their  removal 
became  necessary.  They  were  cut  off  to  a  level  with 
the  gums  Avith  the  bone-forceps,  the  tongue  was  scari- 
fied and  bathed  with  a  cold  lotion,  and  the  animal  was 
fit  for  work  at  the  end  of  a  week. 

"  Perhaps  at  first  it  may  seem  better  practice  in  such 
eases  to  extract  the  tushes  entirely.      But  when  the 


156  THE  PATHOLOGY  OF  THE  TEETH. 

length  and  obliquity  of  their  roots  and  the  fact  of  their 
being  situated  in  the  weakest  part  of  the  jaw  are  con- 
sidered, it  is  plain  that  such  a  procedure  would  in  all 
probability  be  followed  by  the  most  serious  results, 
such  as  fracture  of  the  jaw,  osteo-sarcoma..  &c.,  the 
former  having  happened  under  our  own  observation." 

The  surgeons  recommend  (as  auy  intelligent  person 
would)  the  removal  of  supernumerary  or  abnormal  in- 
cisor teeth.  AYhen  the  tooth  is  without  the  normal 
range  it  interferes  with  the  prehensile  function  of  the 
lips;  when  within,  it  interferes  with  the  tongue.  The 
former,  they  say,  may  either  be  cut  off  with  the  bone- 
forceps  or  extracted.  In  the  latter  case,  however,  they 
prefer  to  cut  them  off,  but  admit  that  some  teeth  re- 
quire extraction,  for  wdiich  the  use  of  the  crank-forceps 
is  recommended. 

The  Treatment  of  Caries  is  the  next  subject  consid- 
ered. '■'  The  only  remedy  for  caries,"  the  surgeons  say, 
"in  the  great  majority  of  cases,  is  the  extraction  of  the 
tooth.  If  we  were  called  on  to  treat  the  disease  at  its 
beginning,  cauterizing  the  black  spot  would  check  its 
progress ;  but  when  the  dental  bulb  has  been  attacked, 
the  extraction  of  the  tooth  is  the  only  remedy." 

The  instrument  recommended  for  extracting  teeth 
is  the  forceps,  and  under  ordinary  circumstances,  the 
surgeons  say,  fracture  of  the  jaws  ought  not  to  occur. 
They  mention  as  useful  instruments  the  key  invented 
by  M.  Garengeot,  the  mouth -screw  by  M.  Plasse,  and 
the  lever-forceps  by  Prof.  Simonds,  but  say . 

*^  Instances  occur  in  which  the  carious  tooth  cannot 
be  seized  by  any  of  these  instruments.  For  example, 
when  the  last  upper  grinder  is  diseased,  it  is  sometimes 


THE  PO\YEK   OF  THE  TOXGUE.  157 

impossible  to  dilate  the  month  sufficiently  to  slide  the 
instrument  between  it  and  the  corresponding  lower 
tooth.  Besides,  the  tongue,  however  firmly  it  may  be 
held  outside  the  month,  has  still  the  power  to  displace 
the  instrument  by  the  energy  of  the  undulatory  move- 
ments at  its  base.  Again,  the  back  grinders,  having 
ordinarily  shorter  Ijodies  than  the  others,  afford  less 
hold  for  the  instrument.  In  some  cases  they  afford  no 
hold  at  al],  as  their  bodies  are  worn  almost  to  a  level 
with  the  gums. 

^'Lastly,  in  some  cases  the  exostosis  of  the  root  of 
the  tooth  is  so  great  that  it  is,  as  it  were,  wedged  in 
the  socket,  and  resists  all  efforts  to  extract  it.  What 
is  to  be  done?  The  disease  may  lead  to  grave  local 
complications  and  dangerous  general  disorders.  In 
such  a  case  we  would  recommend  trephining  the  dis- 
eased sinus  and  punching  the  tooth  mto  the  mouth. 
This  operation  being  very  unusual,  and  the  observance 
of  some  rules  requisite  for  practicing  it,  we  will  con- 
sider it  somewhat  in  detail. 

''If,  as  sometimes  happens,  the  swelling  over  the 
sinus  is  indistinct,  it  would  be  well  to  be  guided  by  a 
prepared  head,  in  order  to  apply  the  trephine  in  the 
exact  place,  which  is  above  tlie  diseased  root.  A  large 
V  or  crucial  incision  should  be  made,  and  the  trephine 
manipulated  till  the  sinus  is  laid  open.  The  opening- 
should  be  extensive  rather  than  confined;  it  is  more 
convenient  to  apply  upon  the  parietes  of  the  sinuses 
three  crowns  of  the  trephine,  tangent  reciprocally  at 
their  circumferences;  then,  by  the  aid  of  a  sharp  in- 
strument and  a  small  hammer,  the  angles  may  be  re- 
moved. 

"As  soon  as  the  mucous  membrane  of  the  cavity  has 
been  laid  bare,  the  change  it  has  undergone  may  be 


158  THE  PATHOLOGY   OF  THE  TEETH. 

seen,  and  also  the  vegetations  springing  from  it.  At 
the  bottom  of  the  sinus,  tov/ard  the  alveoUir  border  of 
the  javv.  among  the  vegetations,  is  a  hard,  granulated, 
dry  surface,  resistant  to  the  touch,  of  a  grayish  tint, 
and  analogous  to  sphacelated  bone.  This  is  the  sum- 
mit of  the  root  of  the  tooth. 

"  Ttie  surgeon  then  arms  himself  with  an  iron  punch, 
rounded  at  the  point,  which  he  applies  to  the  root  in 
the  sinus,  and  having  further  separated  the  jaws  by  a 
few  turns  of  the  speculum  oris,  commands  an  assistant 
to  strike  short,  hard  blows,  the  surgeon  looking  at  tlie 
tooth  to  see  the  effect  of  each  blow.  Usually  the  tooth 
soon  gives  way,  and  falls  into  the  mouth  generally  in 
two  fragments,  according  to  the  direction  of  the  caries. 
Sometimes,  however,  from  the  length  of  the  tooth,  it 
cannot  be  punched  entirely  into  the  mouth,  being 
stopped  by  the  opposite  lower  tooth;  but  it  may  be 
wrenched  out  with  a  pair  of  long  pincers,  the  handles 
of  which  should  be  separated  to  increase  the  power  of 
the  operator.  When  the  operation  is  terminated,  the 
vegetations  of  the  mucous  membrane,  as  far  as  they 
can  be  reached,  must  be  excised.  To  stop  the  hem- 
orrhage, and  to  modify  the  state  of  the  membrane, 
pledgets  of  tow,  moistened  with  a  diluted  solution  of 
nitric  acid,  or  some  other  caustic,  should  be  applied. 

"It  is  really  extmordinary  with  what  rapidity  the 
structural  breaches  resulting  from  this  operation  are 
restored  by  the  reparatory  efforts  of  the  organic  econ- 
omy. The  first  time  we  performed  the  operation  we 
doubted  the  animal's  recovery.  The  sinuses,  laid  open 
by  a  breach  nearly  two  inches  and  a  half  in  diameter, 
communicated  with  the  mouth  by  an  enormous  open- 
ing, the  root  of  the  tooth  having  acquired  nearly  three 
times  its  normal  volume.     The  lininsr  membrane  of 


THEATMEXT  AFTEU  TllEPHIXIKG.  159 

the  maxillary  sinuses,  and  the  frontal  also,  had  suffered 
the  transformation  already  described  to  its  greatest 
degree.  -And,  finally,  it  required  efforts  almost  beyond 
belief  to  loosen  the  tooth  and  force  it  from  its  socket. 
Still  the  animal  made  a  good  recovery. 

"  Tlie  treatment  following  the  operation  sliould  be 
as  follows:  Assiduous  attention  to  cleanUness  is  nec- 
essary from  the  tirst.  On  the  first  day  the  animal 
should  be  deprived  of  all  solid  or  fibrous  food;  in  fact, 
a  little  thin  gruel  is  all  it  requires,  and  the  mouth 
should  be  gargled  with  m  acidulated  fluid  even  after 
its  use.  The  fluid  may  be  applied  with  an  ordinary 
syringe.  Bleeding  is  often  required,  the  quantity  of 
blood  to  be  abstracted  depending  on  the  energy  of  the 
reaction  following  the  operation. 

"  On  the  day  after  the  operation  the  dressing  should 
be  raised.  The  interior  of  the  sinus,  cauterized  with 
nitric  acid,  reflects  a  blackish  tint.  The  odor  is  repug- 
nant, and  there  are  generally  some  remains  of  putrid 
alimentary  matters,  mixed  with  clots  of  blood,  in  the 
sinus.  Detergents,  such  as  Lebarraque's  chlorinated 
solution  of  soda,  mixed  with  a  gentian  wine,  should  be 
injected  into  the  sinus  and  the  mouth  cleaned  with 
acid  gargles ;  a  firm  pledget  of  chlorinated  tow  should 
be  introduced  into  the  socket,  to  prevent  anything 
passing  from  the  mouth  to  the  sinus.  The  regimen 
should  consist  of  gruel  only,  the  gargles  to  be  used 
often  during  the  day. 

"  On  the  second  day  the  borders  of  the  sinus  will  be 
a  little  swollen.  Reparatory  work  has  begun  in  the 
cauterized  membrane;  the  eschars  detach  themselves, 
exposing  a  rosy  surface  of  favorable  aspect  to  the  view. 
The  odor  is  less  repugnant.  Continue  the  aromatic 
detergent  injections,  the  same  food,  with  the  addition 


160  THE  PATHOLOCrY   OF  THE  TEETH. 

of  a  little  bran,  and  gargle  often.  As  suppuration  be- 
gins to  establish  itself,  the  dressings  should  be  renewed 
two  or  three  times  during  the  twenty-four  hours. 

"  It  is  not  our  intention  to  indicate  the  progress  of 
the  wound  and  the  attention  it  demands  from  day  to 
day.  The  tumeOed  bones  and  other  structures  in  the 
region  of  the  wound  proportionally  lessen,  and  the 
membrane  of  the  sinus  takes  on  a  uniformly  rosy  tint 
and  the  glistening,  humid  aspect  proper  to  a  mucous 
membrane.  The  nasal  flux  finally  ceases,  the  matter 
that  may  be  secreted  finding  an  outlet  through  the 
alveolus  into  the  mouth.  The  opening  made  by  the 
trephine  contracts  itself  by  degrees,  but  in  extreme 
cases,  like  the  one  we  have  described,  it  is  never  suffi- 
cient to  entirely  repair  the  structures  cut  away.  It 
may  be  hidden,  however,  by  a  leather  or  metallic  plate, 
attached  to  the  check  of  the  bridle." 

The  surgeons  claim  that  the  resort  to  this  seyere 
mode  of  extracting  teeth  is  justified  by  the  success  of 
the  operation  and  its  concomitant  results,  namely,  the 
advantage  of  injecting  the  sinuses  and  preventuig  un- 
healthy secretions  by  them,  and  the  stopping  of  the 
discharge  from  the  nose,  wdiich  had  aroused  suspicion 
of  glanders.  They  furthoy  say — and  a  better  argument 
in  favor  of  veterinary  dentistry  could  not  w^ll  be  ad- 
vanced— that  they  believe  glanders  is  often  .caused  by 
the  neglect  of  diseased  teeth,  and  "that  the  modus 
operandi  of  its  production  in  such  cases  may  be  ex- 
plained on  the  ground  of  the  absorption  of  pus  by  the 
constitution." 

Of  trephining  the  sinuses  they  further  say: 

"  "We  have  treated  many  cases  of  caries  successfully 
by  simply  trephining  the  frontal  and  maxillary  sinuses 


CARIES  OF  THE  SOCKET   BOXES.  161 

and  injecting  detergents;  bnt  in  a  far  greater  number 
the  treatment  has  been  unsuccessful.^-  Yet  we  believe 
that  it\  in  addition  to  trephining,  the  teeth  had  been 
extracted,  and  a  communieation  established  between 
the  sinus  and  the  mouth,  the  results  would  have  been 
more  favorable. 

"  Monsieur  Delafond,  in  his  memoir  on  the  evulsion. 
of  the  teeth,  publislied  in  1831,  says  the  operation  of 
trephining  is  ouly  practicable  in  the  case  of  the  tliree 
first  grinders,  it  being  necessary  in  the  case  of  the  three 
last  to  make  an  incision  through  the  zygomatico-maxil- 
laris  muscb  and  the  nervous  plexus  which  is  formed 
on  it.  We,  on  the  contrary,  claim  that  the  fifth  pair 
of  nerves  will  be  injured  in  opeii^ting  on  the  three  first 
teeth,  but  that  there  will  be  little  injui'y  to  the  muscle 
in  the  case  of  the  three  lasL" 

The  memoir  concludes  as  follows : 

^'Caries  Attacking  the  MaxiTlarij  Bone  after  tlie  Ex- 
traction of  the  Teetlu — When  caries  of  a  tooth  has  in- 
duced consecutively  interstitial  suppuration  of  the 
spongy  tissue  of  the  socket,  it  is  possible  that,  even 
after  the  extmetion  of  the  tooth,  the  disease  may  at- 
tack the  bone.  Then,  more  than  ever,  may  we  dread 
the  tumefaction  of  the  tissues  and  sarcomatous  altera- 
tions, which  are  ordinarily  the  I'esult  of  persistent  sup- 
puration in  the  areoloB  of  the  sj^ongy  substance  of  the 
bones.  To  prevent  these  dangerous  consequences,  the 
socket  should  be  cauterized  with  the  actual  cautery, 

*  "  Sinnses  that  may  have  formed  by  the  matter  from  ab- 
scesses in  the  alveolar  processes  eating  its  way  through  the  wall 
of  the  alveoiris.  and  which  may  "open  either  on  some  part  of  the 
face  or  within  the  mouth,  are  seldom  treated  with  the  success 
one  could  desire." — Proj\  George  Vfi'mell^ 


162       THE  PATHOLOGY  OF  THE  TEETH. 

and,  if  it  is  practicable,  a  counter  opening  l)y  trephin- 
ing sliould  be  made.  In  some  cases  m  our  practice 
this  mode  of  treatment  produced  the  most  satisfactory 
results.  If,  however,  on  account  of  the  circumstances 
of  the  ease,  the  actual  cautery  cannot  be  used,  a  strong 
solution  of  argeuti  nitras,  applied  with  pledgets  of  tow 
or  lint,  may  be  substituted. 

"  Complications  of  Operations  on  tlie  Mouth. — One  of 
the  most  ordinary  and  serious  complications  of  opera- 
tions on  the  mouth  is  the  excoriation  of  the  'bars'  by 
the  friction  of  the  speculum  oris.  The  denuded  bone 
often  exfoliates,  rendering  the  horse  unht  for  work  for 
a  month  or  more.  The  evil  may  be  avoided  by  envel- 
oping the  transverse  bars  of  the  speculum  with  tow  or 
some  other  elastic  material,  and  by  being  expeditious 
in  operating.  The  hemorrhage,  which  is  never  abun- 
dant enough  to  be  serious,  may  be  checked  by  pledgets 
of  tow,  wet  with  a  solution  of  either  nitric  or  sulphuric 
acid. 

''  Regimen. — The  regimen  in  extreme  cases  of  caries 
has  already  been  indicated  in  the  account  of  the  case 
of  trephining  for  caries  and  exostosis  of  the  root  of  a 
grinder.  In  addition  to  well-boiled  gruel,  mixed  or 
unmixed  with  bran,  carrots  and  similar  food  will  be 
found  beneficial."* 

*  As  horses  with  defective,  diseased,  or  worn-out  teeth  require 
sof^,  or  orround  food,  a  few  extracts  from  tlie  article  on  "Food" 
in  Praf.  Youatt's  work  entitled  "The  Horse"  (p.  133)  and  other 
sources  will  not  be  out  of  place  here :  "  Oatmeal  gruel  consti- 
tutes one  of  the  most  important  articles  of  diet  for  the  sick 
horse.  Few  c:rooms  make  good  gniel.  It  is  either  not  boiled 
long  enongh.  or  a  sufficient  quantity  is  not  used.  The  propor- 
tions should  be  a  pound  of  meal  to  a  gallon  of  water.  It  should 
be  constantly  stirred  till  it  boils,  and  for  five  minutes  afterward. 
Carrots,  according  to  Stewart's  '  Stable  Economy,'  are  a  good 


PEOF.  VARi^ELL'S  VIEWS.  163 

Prof.  George  Varuell,  of  the  Royal  Veterinary  Col- 
lege of  London,  the  autlior  of  a  series  of  articles  "On 

substitute  for  grass,  and  in  sick  or  idle  horses  render  corn  un- 
necessary. Tliey  improve  the  state  of  the  skin.  At  first  they 
are  "slightly  diuretic  and  laxative,  but  the  effect  lessens  with  use. 
Half  a  bushel  is  a  large  daily  allowance.  Swedish  turnijis  and 
raw  potatoes  are  useful  foods.  Raw  potatoes,  sliced  and  mixed 
with  chaff,  may  be  given  to  advantage,  but  it  is  better  to  boil  or 
steam  them,  as  purging  rarely  ensues.  For  horses  recovering 
from  sickness,  barley  in  the  form  of  malt  is  serviceable  as  tempt- 
ing the  appetit3  and  recruiting  the  strength.  It  is  best  given 
in  mashes,  water  somewhat  below  the  boiling  heat  being  poured 
upon  it,  and  the  vessel  kept  covered  for  half  an  hour.  Rye  is 
used  in  Germany,  but  generally  cooked  as  bread,  which  is  made 
from  the  whole  flour  and  bran.  It  is  not  unusual  in  traveling 
through  some  parts  of  Germany  and  Holland  to  see  the  postil- 
ions help  themselves  ani  their  horses  from  the  same  loaf.  In 
some  northern  countries  peameal  is  frequently  used,  not  only  as 
food,  but  as  a  remedy  for  diabetes.  Linse^^d,  rau^  ground,  or 
boiled,  is  sometimes  given  to  sick  horses.  Half  a  pint  may  be 
mixed  with  the  feed  every  night.  It  is  supposed  to  be  useful  in 
cases  of  catarrh.  It  is  very  useful  for  a  cough,  but  it  is  too 
nutritious  for  a  fever.  For  a  cough  it  should  be  boiled  and 
given  in  a  bran  mash,  to  which  two  or  three  ounces  of  coarse 
sugar  may  be  added.  Tares,  cut  after  the  pods  are  formed,  but 
some  time  before  the  seeds  are  ripe,  lucern,  and  sainfoin  are 
useful  foods.  Of  the  former  the  variety  known  as  vicia  sativa 
is  the  best." 

On  page  511  Prof.  Youatt  says  "  some  greedy  horses  habitu- 
ally swallow  their  food  without  properly  grinding  it."  As  a 
remedy  he  recommends  that  chaff  be  mixed  Avith  the  corn,  oats, 
or  beans,  which,  being  too  hard  and  sharp  to  be  sw^allowed  with- 
out chewing,  compels  the  horse  to  mosticate  his  food.  He  says : 
"  Chaff'  may  be  composed  of  equal  quantities  of  clover  or  meadow 
hay  and  wheateu,  oaten,  or  barley  straw,  cut  in  pieces  of  a  quar- 
ter  or  a  half  an  inch  in  length,  and  mixed  well  together.  The 
allowance  of  corn,  oats,  or  beans  is  added  afterward,  and  mixed 
with  the  chaff.  Many  farmers  very  proy)erly  bruise  the  oats  and 
beans.     The  wdiole  oat  is  apt  to  sbp  out  of  the  chaff  and  be  lost. 


164       THE  PATHOLOGY  OF  THE  TEETH. 

Some  of  the  Diseases  Affecting  the  Facial  Region  of 
tlie  Horse's  Head"  (^"Veterinarian/"'  18GG-GT),  and 
other  productions,  has  made  the  disorders  of  horses' 
teeth  a  study,  and  has  aided  somewhat  in  clearing  the 
^•mystery''  that  Surgeon  Gowing  believes  will  "to  a 
certain  extent  always  remain/'  for  he  has  succeeded  in 
casting  some  light  on  the  Eetiology  of  a  tooth's  greatest 
enemy — caries.  His  suggestion  as  to  plugging  teeth 
with  gutta-percha  is  novel,  and  in  some  cases  might 
be  practicable.  However,  would  not  cement,  which 
gives  such  perfect  satisfaction  in  human  dentistry,  be 
preferable  ?  It  is  not  expensive,  and  can  be  as  readily 
introduced  into  a  cavity  as  gutta-percha;  besides,  as 
the  cavity  must  first  be  thoroughly  cleaned  (no  matter 
which  is  used),  its  use  in  the  end  might  save  time  and 
the  tooth  be  much  longer  preserved.  A  horse's  tooth 
that  can  be  got  at  conveniently,  ought  to  be  filled  as 
easily  and,  in  decay  of  its  neck,  perhaps  a3  successfully 
as  a  human  tooth.  Prof.  Varnell's  views  are  in  sub- 
stance as  follows  ("Veterinarian,"  1867): 

"Caries  of  the  roots  of  the  grinder  teeth  is  rare  and 
generally  very  difficult  to  account  for.  I  think  that, 
in  the  majority  of  cases,  it  depends  upon  external  vio- 

For  old  horses,  and  for  those  with  defective  teeth,  chaff  is  pecu- 
liarly useful,  and  for  both  classes  the  grain  should  be  broken  as 
well  as  the  fodder.  The  proportions  are  eight  pounds  of  oats 
and  two  of  beans  to  twenty  of  chaff." 

Concerning  swallowing  without  grinding  Prof.  Youatt  further 
says:  "In  cases  of  this  kind  the  teeth  should  be  examined. 
Some  of  them  may  be  unduly  lengthened,  particularly  the  first 
of  the  grinders,  or  their  ragged  edges  may  wound  the  cheek.  In 
the  former  case  the  horse  cannot  properly  masticate  his  food ; 
in  the  latter  he  will  not,  for  horses,  as  too  often  occurs  in  sore 
throat,  would  rather  starve  than  put  themselves  to  much  pain." 


THE  ALYEOLO-DEXTAL  PERIOSTEUM.  165 

lence,  although  we  are  not  always  able  to  trace  it  to 
such  a  cause.  Inflammation  of  the  alveolo-deutal  peri- 
osteum, especially  where  it  surrounds  the  root  or  roots 
of  a  tooth,  would  tend  to  this  result.  Other  causes 
may  produce  the  same  effect.  Indeed,  whenever  or 
however  effected,  when  the  nutrition  of  any  part  of  a 
tooth  ceases,  decay  is  likely  to  follow.  When  caries 
begins  from  within,  it  is  due  to  cessation  of  nutrition, 
arising  perliaps  from  disease  of  only  a  part  of  the  cen- 
tral pulp  of  the  tooth.  If  from  without,  it  arises  from 
the  periodontal  membrane  v/here  it  meets  the  gum. 

"  Caries  of  the  cervix  (neck)  of  the  tooth  is  much 
more  common  than  it  is  in  the  root ;  still  it  does  not 
occur  in  more  than  one  horse  in  five  hundred.  The 
question  will  naturally  be  asked,  To  what  does  this 
tendency  to  decay  belong  ?  Under  such  circumstances 
are  we  not  forced  to  the  conclusion  that  it  must  de- 
pend either  upon  a  defective  structure  of  the  tooth,  or 
that  the  dentine,  enamel,  and  cement  are  dispropor- 
tionately developed,  or  that  one  of  them  is  defective  in 
its  parts?  Another  and  perhaps  the  most  frequent 
predisposing  cause  of  caries  of  the  neck  of  the  grinder 
teeth  is  that  food  becomes  impacted  betw^een  them. 
Its  decomposition  may  not  only  affect  the  teeth,  but 
the  alveolar  processes  also." 

The  professor  believes  that  caries  of  the  crown  of  a 
tooth  is  generally  caused  by  the  horse  biting  on  a  stone 
or  piece  of  metal  during  mastication.  If  the  stone  is 
lodged  in  the  cavity  of  the  infundibulum,  the  pulp  of 
the  tooth  may  be  injured,  for,  to  use  the  professor's 
words,  "  the  thickness  of  the  tooth  between  the  upper 
part  of  the  pulp-cavity  and  the  bottom  of  the  deepest 
infundibula  is  not  very  great." 


166  THE   PATHOLOGY   OF  THE  TEETH. 

Of  the  treatment  of  caries  of  tlie  necks  and  crowns 
of  grinder  teeth,  the  professor  says: 

"As  I  am  not  aware  of  any  treatment  by  which  the 
decaying  process  can  be  stopped,  I  would  as  an  experi- 
ment in  suitable  cases — that  is,  in  those  in  which  the 
diseased  part  may  be  got  at — phig  the  tooth  with  gutta- 
percha, having  first  thoroughly  cleaned  the  cavity.  If 
the  plug  can  be  retained  in  its  place,  some  benefit  may 
be  derived  fi'om  its  use.  Beheving,  however,  that  the 
decomposition  of  food  impacted  between  the  grinder 
teeth  is  one  of  the  exciting  causes  of  their  decay,  I 
would  advise  that  it  be  uow  and  then  removed.  It 
would  not  only  prevent  decay,  but  in  cases  where  decay 
had  already  begun,  would  to  some  extent  check  its  pro- 
gress. Indeed,  1  think  the  health  of  the  horse  would 
in  many  cases  be  improved  by  the  adoption  of  such  a 
plan.'' 

While  the  professor  recommends  gutta-percha  pings 
for  the  crowns  of  slightly  decayed  grinders,  he  says 
that,  compared  with  those  of  the  necks,  they  are  '"less 
likely  to  be  of  even  a  slight  beneflt^  inasmuch  as  the 
plug  would  be  removed  by  attrition."  Where  the  in- 
terior of  the  grinder  is  destroyed  by  disease,  and  the 
usaal  longitudinal  fracture  has  occurred,  he  extracts 
the  tooth  with  the  forceps.  While,  as  a  rule,  the  tooth 
fractures  longitudinally,  the  corners,  he  says,  are  some- 
times broken  off. 

In  commenting  on  the  diseases  of  the  alveolar  pro- 
cesses, Prof.  Varnell  says: 

"The  causes  which  give  rise  to  this  condition  of  the 
maxillary  bones  are  not  easy  to  define.  That  a  horse 
so  affected  is  from  certain  peculiarities  predisposed  to 


DISEASE   OF  ALVEOLAR   PROCESSES.  167 

it,  til  ere  can  be  no  donbt.  For  exam  pi?,  the  teeth  be- 
ing placed  at  a  distance  from  each  other,  thereby  allow- 
ino-  the  food  to  lodo^e  between  them,  must  be  looked 
upon  as  a  predisposing  canse.  A  strumous  diathesis, 
which  I  believe  to  be  more  common  in  the  horse  than 
is  usually  supposed,  must  also  be  regarded  as  a  predis- 
posing canse.  The  particles  of  food  which  become 
impacted  in  these  nnnsually  wide  interdental  spaces, 
after  a  time  decompose  and  give  rise  to  fetid  com- 
pounds, which  act  prejudicially  on  the  parts  they  are  in 
contact  with.  The  membrane  which  covers  the  gums, 
and  also  that  which  lines  the  alveoli  and  is  reflected 
on  the  roots  of  the  teeth,  becomes  inflamed.  The 
inflammation  will  extend  to  the  bone,  the  blood-vessels 
of  which  w'ill  become  enlarged,  as  will  also  the  Haver- 
sian canals  in  which  they  ramify.  The  osseous  lamince 
surrounding  these  canals  will  be  partially  absorbed, 
and  to  some  extent  separated  from  each  other,  and  the 
enlarged  spaces  thns  produced  will  be  filled  with  in- 
flammatory exudation.  Hence  the  soft,  spongy  state 
of  the  gnras  and  their  tendency  to  bleed  from  sHght 
causes ;  hence  also  the  looseness  of  the  teeth  in  the 
alveoli." 

Of  the  deformity  called  Parrot- Moidh,  and  irregular- 
ities of  the  incisor  teeth,  Prof.  Varnell  says : 

"  This  deformity  consists  in  the  upper  incisor  teeth 
projecting  in  front  of  and  overhanging  the  lower  ones 
to  the  extent  in  some  iustances  of  an  inch  and  a  half. 
The  deformity  resembles  the  upper  bill  of  the  parrot, 
w^hich  projects  over  the  lower ;  hence  the  name.  The 
lower  incisors,  from  not  being  worn  off  by  attrition, 
may  become  so  long  that  the  roof  of  the  mouth  is  seri- 
ously injured.     The  deformity  is  generally  associated 


168  THE  PATHOLOGY  OF  THE  TEETH. 

with  an  irregular  position  of  the  upper  grinders  rela- 
tively with  the  lower. 

•'  Sometimes  the  horse,  when  at  pasture,  is  unable  to 
take  a  sufficient  quantity  of  food  to  keep  himself  in 
condition,  and  consequently  he  is  considered  legally 
unsound.  But  if  fed  from  the  manger  he  experiences 
little  trouble  in  collecting  his  food;  nor  will  his  ability 
to  masticate  it  be  interfered  with,  except  perhaps  in 
old  age. 

"  Treatment. — The  treatment  can  only  be  palliative. 
If  the  roof  of  the  mouth  should  become  diseased  and 
mastication  impaired,  the  only  remedy  is  to  reduce  the 
lengtli  of  the  lower  incisors.  The  instrument  generally 
used  is  a  file  or  a  rasp,  but  the  process  is  so  tedious  and 
slow  tinit  it  is  seldom  tiiat  much  good  is  done.  If  the 
sliding-chisel  could  be  brought  to  bear  on  them,  their 
length  could  be  readily  reduced.  Talking  on  the  sub- 
ject with  my  friend,  Surgeon  Gowing,  he  suggested  a 
modification  of  this  instrument  which,  I  think,  would 
answer  very  well. 

*^-' Irregularities  of  the  incisor  teeth,  both  with  refer- 
ence to  their  position  and  number,  are  even  more  com- 
mon than  in  the  grinders,  but  they  seldom  cause  actual 
disease." 

Prof.  William  Williams,  like  Prof.  Varnell,  has  per- 
foraied  his  part  in  elucidating  the  subject  of  caries  of 
the  teeth,  and  he  has  also  illustrated  the  transmission 
of  vitality  to  them  from  the  outside — through  the  me- 
dium of  the  cement— after  it  has  ceased  to  flow  through 
the  pulp  on  the  inside,  the  pulp  having  become  con- 
verted into  dentine.  It  appears  that  anything  that 
disturbs  th6  equilibrium  of  this  flow  of  vitalit}*,  which 
is  the  secret  of  the  growth  of  the  teeth  througliout 


CEMEin:  FILLING  THE  PULP'S  OFFICE.  169 

life,  may  cause  caries.     Prof.  Williams  says  ("  Princi- 
ples and  Practice  of  Veterinary  Surgery,"  p.  470) : 

'^  Caries,  dental  gangrene,  or  decay,  is  almost  exclu- 
sively confined  to  tlie  grinder  teeth — although  I  have 
seen  the  incisors  in  that  condition — and  may  begin 
primarily  in  the  root,  neck,  or  crown  of  the  tooth. 

"  Caries  of  the  root  arises  from  inflammation  of  the 
pulp,  and  may  be  caused  by  a  constitutional  predispo- 
sition or  external  injury.  Inflammation  of  the  pulp, 
however,  does  not  always  cause  caries.  I  have  several 
cases  on  record  where  the  roots  were  enlarged  from 
periodontal  deposit,  with  abscesses  surrounding  the 
roots,  without  caries.  Caries  beginning  at  the  roots 
may  be  due  to  the  obliteration  of  the  pulp-cavity  at 
an  age  when  the  vitality  of  tlie  tooth  depends  upon 
the  integrity  of  the  pulp.  I  need  scarcely  remind  the 
professional  reader  that  the  integrity  of  the  teeth  de- 
pends upon  a  due  supply,  both  as  to  quantity  and 
quality,  of  nutritive  materials. 

"  On  the  roots  of  a  recently  cut  tooth  but  little 
cement  is  met  with  compared  with  that  which  exists 
in  old  teeth.  As  age  advances  the  cement  increases, 
and  the  tooth  grows  from  the  outside.  In  man  it  is 
generally  agreed  that  after  a  given  time  the  dentine 
ceases  to  be  produced,  and  that  the  pulp  is  converted 
into  osteodentine.  In  the  horse  the  pulp-cavity  be- 
comes obliterated  gradually  by  the  pulp  continuing  to 
form  dentine,  the  pulp  simply  giving  way  to  its  own 
product,  which  ultimately  occupies  its  place  and  fills 
its  cavity.  In  proportion  as  the  pulp  diminishes  the 
supply  of  nutriment  is  lessened,  until  at  length  it  is 
entirely  cut  off  from  the  interior;  to  provide  for  the 
vitality  of  the  tooth  the  cement  increases  in  quantity 


170  THE  PATHOLOC^Y   OF  THE  TEETH. 

on  the  root,  and  at  tlie  expense  of  the  perfectly  formed 
dentine  lying  in  immediate  contact  with  its  inner  sur- 
face. That  is  to  say,  this  layer  of  dentine  is  converted 
into  cement  by  the  dentinal  lacunae  undergoing  dila- 
tation and  becoming  identical  with  the  hollow  spaces 
or  cells  of  the  cement.  The  tooth  now  draws  its  nour- 
ishment from  the  blood-vessels  of  the  socket,  and  thus 
continues,  long  after  the  obliteration  of  its  pulp-cavity, 
to  perform  its  part  in  the  living  organism. 

"This  is  the  natural  condition  of  old  teeth.  But 
when  the  pulp-cavity  is  obliterated  at  an  early  age,  by 
a  too  rapid  formation  of  dentine,  and  consequent  ob- 
literation of  the  pulp  when  the  cement  is  not  yet  suffi- 
ciently developed  to  supply  nourishment  to  the  whole 
tooth,  caries  must  be  the  result.  Many  cases  of  caries 
that  have  come  under  my  observation  have  resulted 
from  this  cause,  and  very  often  the  disease  is  confined 
to  that  part  of  the  cement  that  dips  with  the  enamel 
into  the  interior  of  the  tooth,  splitting  it  into  several 
longitudinal  fragments. 

"Caries  of  the  neck  of  the  tooth  is  seen  in  those 
horses  whose  teeth  are  wide  apart,  and  is  caused  by 
the  food  remaining  in  the  interspaces,  and  by  decom- 
position exciting  inflammation  in  the  periodontal 
membrane.  Caries  of  the  neck  is  very  commonly  met 
with  in  the  teeth  of  dogs,  sometimes  causing  abscesses 
in  the  cheek. 

"Caries  beginning  at  the  crown  is  due  to  a  portion 
of  the  dentine  losing  vitality  and  the  power  of  resist- 
ing the  chemical  action  of  the  fluids  of  the  mouth.  A 
portion  of  the  enamel  of  the  crown  may  be  fractured 
by  biting  a  stone  or  piece  of  metal  contained  in  the 
food.  Mere  fracture  of  the  enamel,  however,  is  insuffi- 
cient of  itself  to  lead  to  caries* of  the  teeth  in  the  lower 


SIFTIXG  THE  FEED.  171 

animals,  for  it  is  a  substance  that  is  gradaallj  worn 
off  by  mastication;  but  the  yiolence  whicli  has  caused 
fracture  of  the  enamel,  may  at  the  same  tiine  have 
caused  such  an  amount  of  injury  to  the  dentine  that 
it  dies,  and  progressively  becomes  decomposed.  In 
man  it  seems  there  should  be  death  of  the  dentine  and 
acidity  of  the  oral  fluids  before  caries  can  take  place, 
test-paper  applied  to  a  carious  tooth  invariably  show- 
ing the  presence  of  free  acid,  and  a  very  small  perfora- 
tion in  the  enamel  may  coexist  with  a  considerable 
amount  of  disease  in  the  dentine." 

Surgeon  T.  W.  G owing,  of  London,  a  well-known 
inventor  of  dental  instruments  (veterinary),  in  an 
"Essay  on  the  Diseases  of  the  Teeth  of  the  Horse," 
which  was  printed  in  "The  Veterinarian"  for  1851 
(p.  632),  in  substance  says: 

"I  am  aware  that  the  cause  of  disease  of  the  teeth 
must  to  a  certain  extent  always  remain  a  mystery;  yet 
from  observation  and  reflection  wt  may  be  able  to  de- 
duce conclusions  which  practice  v/ill  confirm. 

"Let  us  consider  the  two  classes  of  horses  that  we 
are  principally  called  upon  to  attend,  namely,  the  cart 
or  draft-horse,  and  the  hack  or  carriage-horse.  So  far 
as  my  observations  have  led  me,  the  latter  class  are 
less  liable  to  diseases  of  the  teeth  than  those  of  a 
coarser  breed.  Now,  may  not  this  be  caused  by  the 
better  care  they  receive  in  the  stable?  The  good  and 
efficient  groom  regularly  sifts  the  provender  previous 
to  feeding  his  horses,  and  thus  rids  it  of  stones,  glass, 
&e.  The  cart-horse  and  the  machine-horse  of  our 
London  omnibus  proprietors,  not  receiving  this  atten- 
tion, are  more  subject  to  diseases  of  the  teeth.  Be- 
sides, it  is  a  common  practice  with  carters  to  sprinkle 


172       THE  PATHOLOGY  OF  THE  TEETH. 

the  provender  with  siilpliuric  acid,  and  we  well  know 
how  acids  affect  the  teeth.  If  such  practices  be  al- 
low-ed,  diseases  of  the  teeth  may  be  readily  accounted 
for. 

"The  teeth  being  lowly  organized,  soon  lose  their 
power  of  self-preservation.  Tney  are  affected  by  the 
general  health  of  the  aDimal.  Should  the  function  of 
the  stomach  or  alimentary  track  be  deranged,  the  teeth 
— from  the  general  health  of  the  animal  being  inter- 
fered with,  and  from  the  local  functional  derangement 
— of  all  parts  of  the  body,  are  the  first  to  suffer  or  de- 
cay. Absorption  of  the  gums,  which  may  be  caused 
by  the  decayed  food  that  lodges  between  the  grinders, 
is  often  followed  by  decay  of  the  cement,  which,  being 
the  most  exterior  as  well  as  tlie  most  highly  organized 
of  the  three  substances  composing  the  teeth,  is  the 
first  to  yield." 

After  describing  the  usual  symptoms  of  diseased 
teeth.  Surgeon  Gowing  asks : 

"  Who  that  has  observed  these  symptoms,  can  hesi- 
tate for  a  moment  to  acknowledge  that  the  animal  is 
suffering  pain,  which,  if  we  were  to  say  arose  from 
toothache,  would  not  be  beheved  by  our  employers?" 

Prof.  W.  Youatt  says  in  substance  ("The  Horse/' 
p.  230) : 

"  Of  the  diseases  of  the  teeth  we  know  little.  Cari- 
ous teeth  are  occasionally  seen.  They  not  only  render 
mastication  difficult,  but  they  sometimes  impart  a  fetid 
odor  to  the  food,  and  the  horse  acquires  a  distaste  for 
aliment  altogether.  Carious  teeth  should  be  extracted 
as  soon  as  their  real  state  is  known,  for  the  disease  is 
often  communicated  to  the  contiguous  teeth  and  to 


FUNGUS  H^MATODES.  173 

the  jaw  also.     Dreadful  cases  of  ^fungus  hsematodes' 
have  arisen  from  the  irritation  of  caries. 

"  Every  horse  that  gets  thin  or  out  of  condition, 
withoLitTever  or  other  apparent  cause,  should  have  his 
teeth  and  mouth  examined,  especially  if,  without  any 
indication  of  sore  throat,  he  'quids'  his  food;  or  if  he 
holds  his  head  to  one  side  while  he  eats,  in  order  to 
get  the  food  between  the  outer  edges  of  his  teeth.  The 
cause  is  irregular  teeth.  Such  a  horse  is  materially 
lessened  in  value  and  is  to  all  intents  and  purposes 
unsound,  for  although  the  teeth  may  be  carefully  sawn 
down,  they  will  project  again  at  no  great  length  of 
time.  A  horse  cannot  be  in  full  possession  of  his  nat- 
ural powers  without  perfect  nutrition,  and  nutrition 
is  rendered  imperfect  by  any  defect  in  mastication." 

Prof.  R.  Owen,  in  his  work  entitled  "A  History  of 
British  Fossil  Mammals  and  Birds  "  (pp.  388-9),  gives 
an  account  of  a  diseased  fossil  horse's  tooth  which  he 
found  at  Cromer.  He  says  he  is  "  induced  to  cite  one 
of  the  curious  examples  of  disease  in  an  extinct  animal 
from  the  rarity  of  its  occurrence  in  the  tissue  which  is 
the  subject  of  it."  The  facts  of  this  rare  case  are  as 
follows: 

"  One  of  the  Cromer  fossil  teeth,  from  the  lower  jaw, 
with  a  grinding  surface  measuring  one  inch  five  lines 
in  long  (an tero- posterior)  diameter,  and  eight  lines  in 
short  (transverse)  diameter,  presented  a  swelling  of 
one  lobe,  near  the  base  of  the  implanted  part  of  the 
tooth.  To  ascertain  the  nature  and  cause  of  this  en- 
largement, I  divided  it  transversely,  and  exposed  a 
nearly  spherical  cavity,  large  enough  to  contain  a 
pistol-ball,  with  a  smooth  inner  surface.  The  parietes 
of  this  cavity,  composed  of  dentine  and  enamel  of  the 


174  THE   PATHOLOGYOF  THE  TEETH. 

natural  structure,  were  from  one  to  two  lines  and  a 
half  thick,  and  were  entire  and  imperforate.  The 
water  percolating  the  stratum  in  which  this  tooth 
had  lain,  had  found  access  to  the  cavity  through  the 
porous  texture  of  its  walls,  and  had  deposited  on  its 
interior  a  thin  ferruginous  crust;  but  the  cavity  had 
evidently  been  the  result  of  some  inflammatory  and 
ulcerative  process  in  the  original  formative  pulp  of 
the  tooth,  very  analogous  to  the  disease  called  'spina 
ventosa'  iu  bone." 


CHAPTER    IX. 

THE   DENTISTRY    OF  THE  TEETH. 

Reports  of  Cases  Treated  by  Various  Surgeons.— Gutta-Pcrclia 
as  a  Filling  for  Trepliined  Sinuses.— Teeth  Pressinor  against 
the  Palate.— Passing  a  Probe  through  a  Decayed  Tooth.— 
Death  of  a  Horse  from  Swallowing  a  Diseased  Tooth. 

Horsemen,  farmers,  and  other  practical  men  will 
find  much  usefal  information  in  the  present  chapter, 
for  it  is  based  on  the  experiences  of  Veterinary  Sur- 
geons, whose  reports  appear  in  the  various  volumes  of 
"The  Veterinarian"  (printed  monthly  in  London), 
and  to  which  I  am  so  mnch  indebted  for  other  useful 
information.  It  is  probably  not  too  much  to  say  that 
the  more  generally  the  chapter  is  read  the  fewer  horses 
will  be  killed  in  the  future  for  having  decayed  teeth, 
accompanied  with  a  discharge  from  the  nostril. 

In  "The  Veterinarian"  for  1856  (p.  437)  Surgeon  J. 
Horsburgh  reports  the  following  interesting  case,  en- 
titled "  Chronic  Is^asal  Gleet  produced  by  a  Diseased 
Tooth:" 

"About  twelve  months  ago  I  was  consulted  about 
the  case  of  a  mare  with  a  discharge  from  the  near  nos- 
tril. She  had  been  under  treatment  for  eighteen 
months,  and  the  superior  maxillary  sinus  had  been 
opened  with  the  trephine.  The  discharge,  however, 
continued   to   flow,  both   from   the  nostril   and  the 


176  THE   DENTISTRY  OF  THE  TEETH. 

wound,  notwithstanding  the  trephining  had  been  per- 
formed a  year  before  I  saw  the  animal 

^'  The  defluction  had  an  offensive  smell,  and  the  sub- 
maxillary gland  was  enlarged,  causing  suspicion  of 
glanders.  The  opening  had  been  made  a  little  too 
high,  so  that  the  central  instead  of  the  superior  part 
of  the  sinus  was  perforated.  I  found  that  the  whole 
mischief  was  caused  by  a  diseased  tooth.  With  the 
assistance  of  a  smith  I  removed  the  tooth,  which  was 
split  up  its  middle  and  considerably  decayed.  It  was 
more  than  two  inches  long,  and  was  bent  forward  to- 
ward the  cheek.  The  odor  was  most  offensive.  I  then 
opened  the  frontal  and  maxillary  sinuses,  both  of 
which  were  filled  with  fetid  pus.  The  wounds  were 
first  treated  with  a  weak  solution  of  chloride  of  lime, 
and  subsequently  with  an  ordinary  astringent  lotion. 
In  addition  to  the  local  treatment,  I  administered  the 
diniodide  of  co23per. 

"After  a  considerable  time  the  wounds  were  allowed 
to  heal,  and  the  mare  appeared  much  better.  But  very 
shortly  the  discharge  began  to  flow  again  worse  than 
ever,  and  the  smell  was  almost  intolerable.  Deter- 
mined, if  possible,  to  make  a  cure  of  the  case,  I  cut 
into  the  sinus  again  with  the  skull-saw,  taking  out  a 
triangular  piece  of  bone  about  two  inches  long  by  one 
inch  and  a  half  broad.  At  the  upper  part  of  the 
cavity  I  found  some  masticated  food  in  a  state,  of  de- 
composition. It  had  passed  through  the  alveolns  into 
the  sinus.  Fractured  bones  were  removed,  and  the 
opening  being  extended  through  into  the  nostril,  a 
small  mstniment  could  be  passed  down  it  into  the 
month.  A  weak  nitric  acid  lotion  was  used  to  induce 
fresh  inflammatory  action,  and,  if  possible,  to  fill  up, 
by  an  effusion  of  lymph,  the  passage  through  which 


CURED  INSTEAD  OF  KILLED.         177 

the  food  was  pressed  upward  from  tlie  month  into  the 
cavity.  The  external  wound  was  dressed  with  an 
ordinary  healing  lotion,  and  tow  was  put  into  it  daily, 
and  pressed  downward  to  the  mouth.  A  little  blister 
liniment  was  also  occasionally  applied. 

"Before  operating,  the  frontal  sinus  on  the  affected 
side  was  considerably  more  bulging  than  the  other.  It 
is  now  reduced,  and  the  wouud  has  healed.  The  dis- 
charge from  the  nose  has  stopped,  and  there  is  no 
smell.  Thus,  after  about  two  years  and  a  half  of 
treatment,  this  mare,  now  only  five  years  old,  is  able 
to  resume  her  work,  and  has  every  appearance  of  being 
likely  to  remain  well. 

"  Had  I  not  been  able  to  effect  a  cure  by  the  closing 
of  the  passage  into  the  mouth,  I  would  have  tried 
filling  it  with  gutta-percha.  If  a  discharge  were  to 
take  place  again  in  this  case,  it  would  no  doubt  depend 
on  the  existence  of  a  small  aperture,  and,  under  such 
circumstances,  I  should  not  hesitate  to  again  cut  into 
the  sinus  and  endeavor  to  close  the  opening  in  the 
bone  with  gutta-percha,  or  some  similar  substance.'' 

Surgeon  H.  Surmon,  in  an  article  "'  On  the  Extrac- 
tion of  Projecting  Teeth,"  tells  how  lie  saved  a  horse 
that  had  been  ordered  killed  by  its  owner  ("Veterina- 
rian," vol.  ii,  p.  25): 

"Last  year  a  neighbor  of  mine  had  a  horse  which 
had  been  losing  flesh  for  some  time,  and  his  appetite 
was  gradually  diminishing.  When  I  first  examined 
the  horse  I  saw  no  appearance  of  disease  that  could 
affect  his  appetite,  and  looking  at  his  mouth  I  per- 
ceived no  laceration  of  the  cheeks  or  other  injury. 
The  horse  grew  worse,  became  almost  a  skeleton,  and 
its  owner  ordered  that  it  be  killed.     Being  informed 


1T8  THE  DEXTISTRY  OF  THE  TEETH, 

of  the  fact,  I  expressed  a  wish  to  examine  his  month 
once  more.  I  accordingly  pnt  a  balling-iron  into  his 
mouth  and  introduced  my  hand,  and  at  the  extremity 
of  the  grinders  I  found  two  teeth,  one  on  each  side  of 
the  lower  jaw,  which  had  grown  long  enough  to  press 
into  the  roof  of  the  mouth,  and  thus  prevented  the 
animal  from  eating.  I  endeavored  to  extract  these 
teeth  with  an  instrument  similar  to  that  used  for  the 
human  teeth,  but  without  effect,  as  it  could  not  be 
got  on  them.  I  then  contrived  an  instrument  which 
was  very  simple.  When  it  was  passed  up  the  mouth, 
the  tooth  became  fixed  between  the  divided  end  of  the 
iron ;  the  handle  being  then  turned,  the  tooth  was 
extracted  with  the  greatest  ease.  From  that  moment 
the  horse  began  to  feed,  and  rapidly  improved  in  con- 
dition. In  a  short  time  he  went  to  work,  and  has  done 
well." 

Surgeon  C.  May,  of  Maiden,  Eng.,  thus  tells  how  he 
cured  "A  Case  of  Disease  of  the  Jaw"  ('*  Veterinarian," 
1834,  p.  93): 

"  I  was  requested  by  Mr.  Ram,  of  Purleigh,  to  look 
at  a  horse  whicl)  he  told  me  had  a  'cancer'  in  his  jaw. 
1  found  my  patient,  a  fine  young  chaise-horse,  looking 
very  poor,  and  having  a  constant  discharge  from  the 
region  of  the  root  of  the  second  lower  grinder.  There 
was  considerable  enlargement  of  the  bone,  which  led 
me  to  suspect  disease  of  the  tooth,  and  which,  on  ex- 
amination, proved  to  be  true.  On  introducing  a  probe 
into  the  orifice,  I  found  that  it  went  through  the  tooth 
into  the  mouth.  I  was  informed  that  this  supposed 
cancer  had  been  under  the  treatment  of  a  farrier,  and 
that  the  poor  beast  had  been  subjected  to  many  pain- 
ful caustic  applications.     As  I  was  satisfied  that  no 


THREE  UPPER  GRIXDERS  EXTRACTED.     1T9 

good  could  be  done  to  the  jaw  as  long  as  the  tooth  re- 
mained in  it,  I  decided  to  extract  it.  I  had  an  instru- 
ment made  similar  to  the  key  used  in  human  dentistry, 
with  a  handle  like  that  of  an  auger.  Having  cast  my 
patient  and  lanced  the  gum,  I  fixed  the  instrument  on 
the  tooth  and  succeeded  in  extracting  it,  although  it 
required  nearly  all  my  strength.  Tliere  was  but 
trifling  hemorrhage,  and  the  'cancer'  soon  got  well. 
I  think  our  patients  are  more  frequently  the  subjects 
of  toothache  than  we  suppose.  Perhaps  ^quidding'  in 
many  of  them  might  be  traced  to  a  carious  tooth." 

In  a  report  of  ten  cases  of  diseased  teeth  that  were 
treated  at  the  Edinburgh  Veterinary  College  during 
the  year  1845,  the  details  of  one  is  thus  given  in  ^'The 
Veterinarian"  (1845,  p.  626): 

"A  cart-horse  was  brought  here  with  a  profuse  flow 
of  white,  clotty,  and  offensively  smelling  matter  from 
the  off  nostril.  The  external  plate  of  the  superior 
maxillary  bone  on  the  same  side  was  considerably 
elevated,  and  pain  was  evinced  on  pressing  the  part. 
There  was  no  ulceration  visible  of  the  Schneiderian 
membrane,  but  the  submaxillary  lymphatic  glands 
were  somewhat  enlarged.  On  examination  there  ap- 
peared to  be  disease  of  the  superior  maxilla,  in  which 
the  grinder  teeth  were  involved.  Considering  the 
extent  to  which  the  facial  bones  were  affected,  it  was 
decided,  as  the  only  way  of  effecting  a  permanent  cure, 
to  extract  the  diseased  teeth.  The  horse  was  cast,  and 
by  means  of  the  ordinary  tooth-key  three  of  the  upper 
back  teeth  were  extracted.  In  a  few  days  after  the 
operation  the  discharge  diminished  in  quantity,  and 
under  the  continued  application  of  proper  remedies  it 
entirely  subsided,  and  the  horse  is  now  well. 


180  THE  DEI^^TISTEY  OF  THE  TEETH. 

"There  are  in  this,  as  in  former  reports,  cases  where 
the  superior  maxillary  bone  and  its  sinuses  have  been 
injured  from  the  elongation  of  the  grinders  of  the  in- 
ferior maxilla,  causing  a  nasal  discharge  in  many  cases 
mistaken  for  that  of  glanders.  They  are  easily  reme- 
died by  shortening  the  teeth  with  the  cutting-forceps." 

Surgeon  A.  H.  Santy  says  ("Veterinarian,"  1875, 
p.  835): 

"On  the  26th  of  Jnne  I  bought  a  six-year-old  mare. 
She  continued  to  work  till  July  17th,  when  she  was 
suddenly  taken  with  a  slight  running  from  the  near 
nostril,  which  greatly  increased  in  twenty-four  hours. 
The  submaxillary  gland  on  that  side  swelled.  There 
was  slight  tenderness  of  the  throat  and  loss  of  appe- 
tite, which  soon  passed  away.  I  showed  the  animal  to 
a  brother  surgeon,  and  told  him  I  thought  of  trephin- 
ing. He  said:  'Don't  be  in  a  hurry.'  It  struck  me 
there  might  be  something  wrong  with  the  grinders.  I 
examined  them,  and  found  the  fourth  superior  near 
side  tooth  with  a  depression  on  the  outside  and  slightly 
raised  from  the  surface  of  the  other  teeth.  There  was 
slight  fetor  from  the  food  lodging  there.  I  at  once 
cast  the  mare,  and  with  some  difficulty  extracted  the 
tooth.  I  then  dressed  the  wound  and  nursed  the  mare 
for  a  few  days.  The  discharge  from  the  nostril  ceased 
in  ten  days.    I  have  the  mare  now  in  constant  work." 

The  above  case  deserves  consideration  for  several 
reasons.  Thousands  of  horses  with  precisely  the  same 
symptoms  have  been  killed  because  the  surgeon  could 
not  discriminate  between  diseased  teeth  and  glanders. 
The  "slight  tenderness  of  the  throat  and  loss  of  appe- 
tite, which  soon  passed  away,"  was  the  result  of  the  pus 


"DOl^T  BE  IIST  A  HFERY."  181 

finding  an  outlet,  which  gave  partial  relief.  Surgeon 
Santy  acted  on  the  advice,  ''  Don't  be  in  a  hurry,"  and 
consequently  had  time  to  think.  The  depression  on 
the  outside  of  the  tooth  and  its  slight  projection  above 
the  common  level,  were  signs  that  the  trained  eye  only 
will  detect.  However,  had  the  operation  been  delayed 
for  a  short  time,  in  addition  to  the  dejoression  on  the 
outside  of  the  tooth,  the  gum  would  have  been  more 
or  less  shrunken,  and  the  tooth,  as  a  natural  conse- 
quence, would  have  appeared  longer.*  Further,  in- 
stead of  the  tooth  being  "slightly  raised  from  the  sur- 
face," it  might  have  been  below  it;  for,  the  inflamma- 
tion having  subsided,  and  the  roots  being  shortened 
by  the  caries,  it  is  liable  to  be  forced  deeper  into  the 
socket.  Its  next  natural  movement,  the  caries  having 
destroyed  its  periosteum,  is  to  drop  out  altogether. 

As  an  ofi*set  to  the  foregoing  cures,  a  few  cases  that 
terminated  in  death  will  be  given.  Surgeon  Samuel 
Baker,  in  a  letter  to  the  editor  of  "  The  Veterinarian  " 
(1845,  p.  216),  says: 

"  I  was  called  in  by  a  neighboring  farmer  to  examine 
a  two-year-old  colt,  which  had  to  all  appearance  a  poly- 
pus as  large  as  a  cricket-ball  growing  out  of  the  right 
nostril.  Respiration  through  that  nostril  was  stopped. 
In  order  to  ascertain  its  nature,  I  had  the  colt  cast, 
and  found  that  the  nostril  was  filled  with  a  hard  fleshy 
tumor,  which  distended  the  other  nostril  also.  After 
making  an  incision  through  the  ala  and  side  of  the 
nostril,  I  removed  a  portion  of  the  tumor,  over  a  pound 
in  weight.     But,  as  still  no  air  passed  through,  and 


*  Shrinkage  of  the  g^im,  according-  to  C.  D.  House,  invariably 
follows  caries  of  the  roots  of  the  teeth. 


182  THE  DEXTISTHY'  OF  THE  TEETH. 

tliera  seemed  not  the  slightest  chance  of  gaining  a 
passage,  I  ordered  the  colt  to  be  killed. 

"  In  dissecting  the  head  I  found  that  the  cause  pro- 
ceeded from  a  decayed  tooth,  at  the  root  of  which  was 
a  bag  of  matter  about  the  size  of  a  walnut,  which  by 
no  possible  means  could  relieve  itself." 

Surgeon  Baker  does  not  say  which  of  the  six  teeth 
(of  course  it  was  an  upper  grinder  of  the  right  side) 
was  diseased.  The  complications  of  the  case  appear  to 
have  been  unusual,  otherwise  the  bag  of  matter  would 
have  sooner  or  later  found  an  outlet  through  the  nos- 
tril. The  extraction  of  the  tooth  would  have  probably 
afforded  an  outlet  through  the  alveolus;  this  failing, 
the  effect  of  trephining  the  sinuses  should  have  been 
tried. 

Surgeon  William  Smith,  of  Norwich,  Eng.,  reports 
a  case  of  caries  of  the  roots  of  several  grinder  teeth, 
accompanied  by  a  discharge  from  the  nostril,  which 
he  admits  he  mistook  for  ozena.  He  says  ("  Veterina- 
rian," 1850,  pp.  381-2) : 

''  I  was  requested  a  few  days  ago  to  visit  a  horse 
which  was  supposed  to  be  ^glandered.'  I  found  the 
animal  in  a  most  emaciated  and  pitiable  condition, 
with  a  copious  greenish  and  very  offensive  discharge 
from  the  left  nostril,  with  slight  tumefaction  of  the 
gland  on  the  same  side.  There  was  no  appearance  of 
ulceration,  but  the  Schneiderian  membrane  had  a 
leaden,  dirty  hue.  Taking  all  the  circumstances  into 
consideration,  I  ordered  the  animal's  destruction,  but 
had  its  head  sent  to  my  infirmary. 

"Meeting  Surgeon  Gloag,  of  the  Eleventh  Hussars, 
I  told  him  I  thought  I  had  a  case  of  ozena.     He  ex- 


OKE  TOOTH  LOST  AXD  FOUR  DISEASED.  183 

pressed  a  wish  to  be  present  at  the  examination  of  the 
head,  and  I  was  glad  to  avail  myself  of  his  assistance. 

"A  lono-itvidinal  cut  was  made  on  each  side  of  the 
septnm  nasi,  and  a  transverse  one  at  a  line  between 
the  center  of  the  orbits.  Another  longitudinal  cut, 
dividing  the  maxillary  sinuses,  was  made  just  above 
the  roots  of  the  grinder  teeth  on  each  side.  By  this 
means  we  had  an  opportunity  of  examining  the  sep- 
tum nasi  on  each  side ;  also  the  turbinated  bones,  and 
the  frontal  and  maxillary  sinuses. 

"  On  the  left  side  we  found  an  accumulation  of  pul- 
taceous  food,  covered  with  tliick  pus,  completely  filling 
the  maxillary  sinus,  and  extending  to  the  turbinated 
bones.  The  frontal  sinus  contained  an  accumulation 
of  inspissated  (thickened)  pus,  the  septum  nasi  was  of 
a  leaden  hue,  as  also  the  membrane  covering  the  tur- 
binated bones,  which  was  much  inflamed  and  thick- 
ened, but  there  was  no  appearance  of  ulceration. 

"  The  difficulty  was  to  ascertain  how  the  food  got 
there.  After  careful  search,  it  was  very  evident  that 
it  could  not  have  passed  through  the  nostril.  We 
therefore  gradually  dislodged  the  food  and  matter, 
searching  for  the  former's  entrance,  and  at  last  found 
a  hole  in  the  alveolar  space  belonging  to  the  last 
grinder,  the  root  of  which  was  completely  gone,  only 
a  small  portion  of  the  crown  itself  remaining.  The 
hole  was  sufficiently  large  to  admit  the  little  finger. 
The  mystery  was  solved— the  process  of  mastication 
had  deposited  the  food  in  the  sinus.  The  fourth 
grinder  was  absent,  having  been  lost  evidently  from 
previous  disease. 

"  On  examining  the  right  side  of  the  bend  we  found 
the  turbinated  bones  and  membranes  covering  the 
septum  nasi  comparatively  healthy,  but  we  discovered 


184  THE  DEI^TISTRY  OF  THE  TEETH. 

a  cyst,  about  the  size  of  a  walnut,  iu  the  maxillary 
sinus.  It  contained  limpid  fluid,  and  occupied  the 
space  immediately  over  the  root  of  the  fourth  grinder 
tooth,  which  was  decayed  and  quite  loose,  and  below'^ 
the  level  of  the  other  teeth.  The  teeth  of  the  lower 
jaw  appeared  healthy.'^ 

Without  further  examination,  Surgeon  Smith  sent 
the  head  to  the  editor  of  "The  Veterinarian,"  who 

says : 

"The  mare  (that  being  the  sex  according  to  the 
teeth)  we  should  take  to  have  been  about  twenty  years 
old.  Her  incisors  are  sound,  and  so  are  the  grinders 
of  the  lower  jaw.  But  in  the  near  (left)  upper  jaw, 
the  second,  fourth,  and  sixth  teeth  are  in  a  state  of 
progressive  decay,  and  the  same  is  true  of  the  fourth 
tooth  of  the  off  side.  The  vacuity  caused  by  the  de- 
fective last  grinder  has  opened  a  passage  to  the  an- 
tnim,  through  which  the  food  has  passed,  and  thence 
into  the  near  chamber  of  the  nose,  between  the  tur- 
binated bones,  where  it  was  discharged  through  the 
nostril.  This  accounts  for  the  irritation  on  this  side 
of  the  head,  for  the  suppurated  and  even  ulcerated 
condition  of  the  Schneiderian  membrane,  and  for  the 
suspicious  discharges.  It  was  evident  enough  that 
there  was  no  glanders.  The  very  circumstance  of.  ali- 
mentary matter  being  discharged  through  the  nostril 
was  enough  to  prove  the  contrary." 

Still  another  case  of  destroying  a  horse  for  what 
merely  appeared  to  be  glanders  is  recorded  by  Prof. 

*  The  italics  are  mine.  Compare  with  comments  on  Surgeon 
Santy's  case,  page  181. 


A  GOVERISTMENT  HORSE'S  HARD  LOT.  185 

William  Percivall  in  his  work  entitled  "Hippopath- 
ology"  (vol.  ii,  p.  237).    He  says: 

"There  are  instances  on  record  of  carions  teeth  be- 
ing productive  of  such  evil  consequences  as  to  lead, 
through  error,  to  a  fatal  termination.  The  following 
relation  ought  to  operate  on  our  minds  as  a  warning 
in  pronouncing  judgment  in  cases  of  glanders,  or  at 
least  in  such  as  assume  the  semblance  of  glanders : 

'^A  horse,  the  property  of  government,  became  a 
patient  of  Surgeon  Cherry  on  account  of  a  copious 
defluetion  of  discolored  and  purulent  matter  from  the 
near  nostril,  unaccompanied  by  submaxillary  tumefac- 
tion, or  by  ulceration  of  the  Schneidenan  membrane. 
For  two  or  three  months  the  ease  was  treated  for 
glanders;  but  no  improvement  following,  a  consulta- 
tion was  deemed  necessaiy,  the  result  of  which  was 
tlie  horse  was  shot. 

"On  examination  of  the  head,  the  third  upper  left 
grinder  proved  to  be  carious,  one-third  of  its  root  be- 
ing already  consumed  and  the  remainder  rotten.  The 
formation  of  an  abscess  within  its  socket  had  loosened 
the  tooth,  and  the  matter  flowing  therefrom  had  estabr 
lished  a  passage  into  the  contiguous  chamber  of  the 
nose.  The  antrum  was  also  in  part  obstructed  by  the 
deposition  of  osseous  matter. 

"This  is  a  case  which,  but  for  the  inquisitiyeness  of 
Surgeon  Cherry,  would  have  merged  into  that  hetero- 
geneous class  of  diseases  passing  under  the  appellation 
of  chronic  glanders. 

"My  father*s  museum  contained  several  specimens 
of  carious  teeth.  One  was  that  of  a  grinder,  the  inte- 
rior of  which  was  black  and  rugged,  from  being  eroded 
by  ulceration,  and  the  roots  had  from  the  same  cause 


186  THE  DEKTISTRY  OF  THE  TEETH. 

mouldered  away.  Two  others  presented  brittle  exos- 
toses upon  their  sides,  forming  spacious  cavities  within 
and  communicating  with  the  contiguous  teeth.  One 
of  them  exhibited  a  perforation  through  which  pus 
appeared  to  have  issued.  Both  seemed  to  have  been 
cases  which  had  origiuated  in  internal  injury." 

Prof.  George  Varnell  closes  his  series  of  papers  "  On 
Some  of  the  Diseases  Atfectiug  the  Facial  Eegion  of 
the  Horse's  Head"  ("Veterinarian,"  1867),  by  giving 
an  account  of  a  case  of  ^osteo-sarcoma,'  the  disease,  in 
his  opinion,  being  jcaused  by  carious  teeth.  The  case 
illustrates  the  importance  of  veterinary  dentistry  ad- 
mirably.    He  says : 

"Further  to  illustrate  varieties  of  the  diseases  of 
the  sinuses,  I  will  relate  a  case  of  osteo-sarcoma  which 
came  under  my  care  in  Jul}^  18G2.  I  found  the  horse 
had  an  offensive  discharge  from  the  left  nostril.  The 
face  below  the  orbit  was  enlarged,  and  the  eye  slightly 
displaced  in  its  cavity.  I  also  found  that  the  three 
last  grinder  teeth  in  the  upper  jaw  of  the  affected  side 
were  quite  loose  in  their  sockets,  from  which  a  dis- 
charge of  a  highly  fetid  character  issued.  Percussion 
on  the  side  of  the  face  indicated  extensive  disease,  and 
the  enlargement  readily  yielded  to  pressure.  As  there 
was  not  the  slightest  prospect  of  a  cure,  I  suggested 
that  the  animal  be  killed. 

''Post-mortem  Examination. — Tlie  outer  walls  of  the 
sinuses,  which  were  very  thin,  were  first  removed,  dis- 
closing a  mass  of  disease  the  seat  of  which  w^as  oppo- 
site the  roots  of  the  fourth  grinder  tooth,  which  was 
carious.  This  abnormal  growth  occupied  the  maxil- 
lary, malar,  lachrymal,  and  a  portion  of  the  frontal 
sinuses,  and  had  also  encroached  upon  the  orbit  to 


swallowi:n'g  a  diseased  tooth.  187 

such  an  extent  as  to  displace  the  eyeball.  The  outer 
surface  of  the  diseased  mass  was  soft  in  texture.  It 
had  a  gelatinous  appearance,  and  when  pressed  with 
the  blade  of  the  scalpel,  a  thin,  watery  fluid  oozed  from 
its  surface.  A  section  of  it  presented  a  grayish-red 
appearance,  with  lightish  streaks  of  fibro-osseous  mat- 
ter diverging  from  its  roots  and  extending  irregularly 
through  its  entire  substance.  The  fiicial  bones  them- 
selves, in  the  region  of  the  disease,  had  in  some  parts 
disappeared  altogether,  while  in  others  the  cancelli 
were  much  enlarged,  their  osseous  partitions  partially 
absorbed,  and  their  interstices  tilled  with  a  deposition 
of  a  fibro-cellular  structure. 

"  Such  is  a  brief  outline  of  this  malignant  and  in- 
curable disease,  which  1  have  no  doubt  primarily  arose 
from  caries  of  the  roots  of  the  grinder  teeth." 

Prof.  Renault,  of  Alfort,  France,  is  the  author  of  an 
interesting  account  of  a  very  unusual  case,  namely, 
the  swallowing  of  a  diseased  tooth  by  a  horse,  which 
appeared  originally  in  the  "'  Recueil  de  Medicine  Vete- 
rinaire"  for  1836.  It  is  an  argument  against  casting 
horses  for  the  purpose  of  extracting  their  teeth,  for 
had  the  horse  been  in  a  standing  position  the  accident 
would  not  have  occurred.  When  a  horse's  head  rests 
upon  the  occiput,  the  muzzle  pointing  upward,  it  is  as 
natural— the  tooth  being  free  of  the  forceps  as  well  as 
the  socket — for  it  to  drop  into  the  throat  as  it  is  for 
water  to  run  down  hill.  The  full  history  of  the  case 
is  as  follows : 

"  A  post-horse,  seven  years  old,  had  not  fed  well,  and 
had  been  losing  flesh  during  about  three  weeks.  On 
the  26th  of  November,  1835,  I  saw  him  for  the  first 
time.     The  postilion  told  me  that  within  the  last  two 


188  THE  DE:t^lSTRY  OF  THE  TEETH. 

days  he  had  eateu  with  more  difficulty  and  pain  than 
before,  and  dropped  almost  the  whole  of  the  hay  and 
corn  from  his  mouth  before  it  was  perfectly  masticated. 
He  had  also  observed  that  during  the  mastication  of 
his  food  the  horse  always  inchned  his  head  to  the  left 
side. 

"On  examining  the  mouth,  I  easily  recognized  the 
cause  of  this  difficulty  of  mastication.  The  gum,  at 
the  second  grinder  of  the  right  lower  jaw,  was  swollen 
and  ulcerated,  both  within  and  without.  The  least 
pressure  on  the  gum  at  this  spot  inflicted  great  pain, 
and  the  animal  also  suffered  when  the  crown  of  the 
tooth  was  touched.  On  that  portion  of  the  jawbone 
contiguous  to  the  diseased  tooth,  was  a  considerable 
swelling,  hot  and  painful,  which  the  postilion  told  me 
had  existed  for  about  twelve  days.  It  was  increasing  in 
size  every  day.  The  breath  was  only  slightly  fetid, 
and  there  was  nothing  to  indicate  caries  of  the  tooth. 
I  expressed  the  opinion  that  the  caries,  if  it  existed,  was 
confined  chiefly  to  the  root  of  the  tooth,  and  that  the 
ulceration  of  the  alveolar  septa  beneath,  of  which  there 
was  no  doubt,  rendered  its  extraction  necessary. 

"  On  the  following  day  the  horse  was  cast,  and  his 
mouth  being  kept  open  by  the  proper  instrument,  the 
key  was  applied  to  the  tooth.  It  resisted  my  first 
eflbrt  to  draw  it,  but,  on  the  second  trial,  gave  way 
with  a  peculiar  sound,  which  made  me  suspect  that  it 
was  broken.  The  instrument  (gag)  was  then  taken 
out  of  the  mouth,  in  order  that  the  tooth  might 
escape,  but,  to  my  great  surprise,  no  tooth  could  be 
seen,  notwithstanding  I  carefully  searched  for  it.  It 
was  now  plain  that  the  tooth  had  been  swallowed.  I 
then  assured  myself  that  the  tooth  had  been  entirely 
extracted,  and  as,  during  the  operation,  the  fraenulum 


OPEN"IKG  THE  JUGULAR.  189 

of  the  tongue  had  been  wounded,  I  deferred  the  cau- 
terization of  the  alveolus  till  the  following  day. 

'•As  to  the  swallowing  of  the  tooth,  I  gave  myself 
very  little  concern.  I  did  not  think  that  so  small  a 
body  was  likely  to  form  any  serious  obstruction  in  the 
intestinal  canal,  or  that  its  temporary  sojourn  in  the 
large  intestine  could  become  at  all  dangerous;  so  I 
merely  directed  that  the  mouth  be  frequently  washed 
with  warm  water,  and  forbade  the  use  of  hard  food. 

"39th.  I  again  saw  the  horse,  and  no  serious  con- 
sequence had  yet  followed  the  operation.  He  ate  bar- 
leymeal  mash  with  appetite,  and  a  small  quantity  of 
hay.  Two  hours  afterward  he  was  brought  to  the 
School.  He  was  very  uneasy,  and  his  belly  was  enor- 
mously distended,  the  swelling  being  principally  on 
the  right  side,  where  the  resonance  was  considerable 
on  percussion.  The  horse  was  continually  endeavor- 
ing to  expel  something  from  the  anus,  and  the  strain- 
ing was  so  great  that  I  feared  the  rectum  would  pro- 
trude. The  efforts  were  followed  by  small  mucous 
dejections,  mixed  with  portions  of  food.  The  mucous 
membrane  was  of  a  subdued  red  color.  These  symp- 
toms had  been  preceded  by  swelling  at  the  flanks; 
colicky  pains  had  followed,  but  they  had  ceased, 
and  nothing  now  remained  except  the  enlargement  of 
the  belly  and  the  incessant  effort  to  expel  the  faeces. 
The  artery  was  full,  but  the  pulse  was  almost  imper- 
ceptible; the  extremities  were  cold  and  the  mucous 
membranes  of  a  red  violet  color.  The  nostrils  were 
convulsively  dilated,  respiration  difficult  and  acceler- 
ated, and  the  walk  staggering;  the  skin  was  covered 
with  sweat,  and,  in  a  word,  the  animal  presented  every 
symptom  of  immediate  suffocation.  On  this  account  I 
immediately  opened  the  jugular  and  abstracted  about 


190  TKE   DENTISTRY   OF  THE  TEETH. 

twelve  pounds  of  blood.  The  patient  was  very  con- 
siderably relieved.  I  then  ordered  all  four  legs  to  be 
well  rubbed  \vith  essential  oil  of  turpentine. 

"There  now  appeared  to  me  a  connection  between 
these  symptoms  and  the  swallowing  of  the  tooth.  But 
where  was  this  tooth  ?  Entangled  in  the  pyloric  ori- 
fice of  the  stomach  ?  I  could  not  perceive  any  symp- 
tom of  gastric  disease.  Was  it  in  the  convolutions  or 
the  caecal  portions  of  the  small  intestines?  How  then 
could  I  explain  the  distention  of  the  large  intestines 
and  the  expulsive  efforts,  so  violent  and  continued? 
It  w^as  more  likely  that  the  tooth  was  lodged  either  in 
the  colon  or  the  caecum,  or  in  the  irregularities  of  the 
floating  colon,  and  partially  or  entirely  prevented  the 
passage  of  the  faeces.  It  was  hard  to  believe  that  in 
the  lapse  of  two  days  the  tooth  could  have  reached  the 
further  part  of  the  intestines. 

"  Having  determined  on  the  nature  of  the  disease,  I 
was  somewhat  embarrassed  to  ascertain  its  precise  seat. 
I  attempted  to  introduce  my  hand  into  the  rectum, 
but  the  circumvolutions  of  the  bowels  were  so  much 
distended  with  gas,  and  so  completely  filled  the  pelvis, 
and  the  mere  introduction  of  my  finger  caused  such 
violent  efforts  to  expel  the  contents  of  the  rectum,  that 
I  was  forced  to  desist. 

'*  In  the  meantime  the  swelling  rapidly  increased, 
and  again  threatened  suffocation.  I  then  determined 
to  use  the  only  means  in  my  power  to  prevent  this, 
namely,  to  puncture  the  csecum.  This  was  effected 
with  the  trocar  used  for  hoove  in  sheep,  and  in  an  in- 
stant the  swelling  subsided,  and  the  symptoms  of  suf- 
focation disappeared.  I  was  then  enabled  to  introduce 
my  hand  into  the  rectum,  but  I  could  not  discover  the 
situation  of  the  tooth.     While  exploring  the  rectum, 


THE  TOOTH   I:N"  THE   C^CUM.  ISl 

however,  the  'canula'  escaped  from  tlie  c:Bcnm.  The 
swelling  now  began  again,  and  increased  with  extraor- 
dinary rapidity.  I  was  about  to  plunge  the  trocar  into 
the  intestines  once  more,  when  I  perceived  that  all 
treatment  was  useless.  The  animal  was  in  the  agonies 
of  death,  and  in  a  few  moments  it  expired. 

"The  post-mortem  examination  took  place  immedi- 
ately after  death.  I  found  in  the  heart  and  lungs  all 
the  lesions  which  usually  accompany  death  by  suffoca- 
tion. The  digestive  canal  was  distended  by  gas.  The 
stomach  was  half  filled  with  barleymeal,  but  not  a  par- 
ticle of  it  was  found  throughout  the  whole  extent  of 
the  small  intestines,  nor  was  there  the  slightest  trace 
of  inflammation  of  the  mucous  coat.  The  caecum  con- 
tained a  great  quantity  of  blood- tin  ted  fluid,  but  there 
was  no  lesion  or  redness  on  any  part  of  its  internal 
face  to  indicate  the  source  of  the  blood.  Probably  it 
came  from  the  wound  made  by  the  trocar. 

"In  the  cavity  of  the  caecum,  toward  its  point,  we 
found  the  tooth ;  but,  I  repeat  it,  there  was  no  inflam- 
mation of  its  mucous  membrane.  There  was,  how- 
ever, a  slight  discoloration  of  the  membrane  toward 
the  end  of  the  colon ;  it  was  of  a  slate  color,  and  was 
probably  caused  by  the  sulphuretted  hydrogen  gas. 

"Are  we  to  conclude  that  the  death  of  the  horse 
was  caused  by  the  tooth?  However  extraordinary 
Buch  a  conclusion  may  at  first  appear,  I  am  very  much 
inclined  to  believe  that  it  affords  the  best  explanation 
of  the  mystery.  The  horse  had  scarcely  eaten  for 
fifteen  days.  This  long  fast  had  produced  a  compara- 
tively empty  condition  of  the  digestive  canal  and  an 
augmentation  of  its  irritability  up  to  the  moment  of 
the  operation.  The  quietness  of  the  horse  and  his 
appetite  and  apparent  health  during  the  two  days  pre- 


192  THE  DEXTISTHY   OF  THE  TEETH. 

ceding  liis  death,  proved  that  the  tootli  passed  without 
obstacle  through  the  first  part  of  the  intestinal  canal. 
Having  arrived  at  the  caecum,  however,  which  was 
almost  empty,  and  lying  for  a  greater  or  less  time  at 
the  inferior  part  of  its  mucous  coat,  its  hard  and  irreg- 
ular sur^ice  produced  irritation ;  and  as  the  contrac- 
tions of  this  intestine  were  not  effectual  to  seize  the 
tooth  and  return  it  to  the  beginning  of  the  colon,  the 
prolongation  of  the  irritation  might  suspend  the  diges- 
tive function  of  this  viscus,  augment  its  secretions, 
and  cause  the  continual  effort  to  expel  the  fseces. 
Hence  also  arose  the  gaseous  distention  of  the  abdo- 
men. As  to  the  death  of  tlie  horse,  the  tooth  was  only 
the  indirect  cause.  The  direct  cause  was  suffocation, 
which  was  produced  by  the  distention  of  the  bowels." 

Prof.  Bouley  and  Surgeon  Ferguson  report  two 
fatal  cases  of  swallowing  teeth  that  came  under  their 
own  observation.  "  In  the  first,"  they  say,  *^  the  horse 
succumbed  in  a  tympanitic  affection,  accompanied  by 
extreme  pain,  and  death  was  produced  by  asphyxia." 
The  second  case,  judging  by  the  short  description  of 
it  in  "The  Veterinarian"  for  1844,  is  the  identical 
case  just  described  by  Prof.  Bouley's  fellow-townsman, 
Prof.  Renault.  Messrs.  Bouley  and  Perguson  further 
say: 

'^Suchj  however,  is  happily  not  always  tlie  result  of 
swallowing  a  tooth  or  the  fragment  of  a  tooth ;  but 
even  the  possibility  of  such  a  result  ought  to  make 
the  surgeon  cautious.  Moreover,  the  swallowing  of  a 
tooth  may  cause  serious  consequences  at  some  future 
time.  We  refer  to  the  formation  of  those  productions 
called  intestinal  calcuH.'  The  tooth,  on  account  of 
its  being  indigestible,  acts  as  the  nucleus  for  the  future 


SWALLOWING  A  S0U:N'D   TOOTH.  193 

calculus,  as  indeed  may  any  similar  body,  which  fact 
has  been  demonstrated  by  Prof.  Morton,  of  the  London 
Veterinary  College,  in  an  excellent  paper  on  'The  For- 
mation of  Calculus  Concretions  in  the  Horse.*"* 

Surgeon  AV.  A.  Cartwright  reports  that  he  extracted 
three  grinders  from  a  'quidding'  mare,  one  of  which 
she  swallowed  ("Veterinarian,"  vol.  iii,  second  series, 
p.  277).  The  tooth  was  sound,  which  may  account  for 
the  favorable  result  of  the  case. 

*  Tlie  Enterprise,  pnblislied  in  Virginia,  Nevada,  in  its  issue 
for  Decambei-  12,  1878,  contains  an  article  entitled  "  A  Stone 
found  in  a  Horse's  Jaw,"  which  is  in  substance  as  follows :  "  For 
a  long  time  a  lump  has  been  noticed  in  the  side  of  the  jaw  of  a 
horse  belonging  to  Superintendent  Osbiston,  of  the  Gould  and 
Curry  and  Best  and  Belcher  mines.  It  was  near  the  jawbone, 
and  no  liniment  had  power  to  soften  or  drive  it  away.  Yester- 
day a  veterinary  surgeon  made  an  incision,  and  to  his  astonish- 
ment removed  a  stone  about  two  inches  long  and  one  inch  in 
diameter.  It  is  yellowish-white  in  color,  and  apparently  as  hard 
as  marble.  Mr.  M.  M.  Frederick,  the  jeweler,  divided  it  longi- 
tudinally, and  in  its  center  was  what  appeared  to  be  a  petrified 
grain  of  barley,  which  was  also  divided  longitudinally.  Around 
this  nucleus  the  stone  had  formed  in  regular  layers,  the  rings  of 
which  could  be  distinctly  traced.  The  material  of  which  the 
stone  was  composed  appeared  to  be  the  same  as  that  of  the  in- 
crustations on  the  tubes  of  boilers.  It  is  conjectured  that  the 
grain  of  barley  pierced  the  gum  and  imbedded  itself  in  the  flesh, 
and  that  the  saliva,  flowing  in,  deposited  limy  matter  similar  to 
that  which  is  sometimes  found  on  the  teeth  of  horses  as  well  as 
men.  A  small  concretion  having  thus  been  formed,  it  gradually 
grew,  the  channel  by  wiiich  the  grain  of  barley  entered  no  doubt 
remaining  open  and  allowing  an  inflow  of  saliva." 

Tiie  above  case  is  another  proof  that  Dr.  Dunglison  was  right 
when  he  said  that  calculi  "may  form  in  every  part  of  the  animal 
body." 

9 


CHAPTER    X. 

FRACTURED      JAWS. 

How  Caused,  and  how  to  Distingnisli  an  Abrasion  of  the  Gums 
from  a  Fracture  of  the  Bone. — Replacing  an  Eye,  Amputa- 
ting part  of  a  Lower  Jaw,  taking  a  Fractured  Tooth  and 
Bones  out  through  the  Nostril,  &c. 

Fractures  of  the  jaws  of  the  horse  are  of  common 
occurrence.  They  may  exist  independently,  but  they 
are  ofton  complicated  with  and  the  cause  of  diseases  of 
the  teeth.  Caries  of  the  jawbone  proper,  and  even 
some  of  the  facial  bones,  is  often  communicated  to  the 
alveoli,  and  when  necrosis  ensues  the  destruction  of 
the  teeth  is  inevitable.  This  is  as  true  in  the  case  of 
the  horse  as  in  that  of  man. 

The  rami  (brandies)  of  the  lower  jaw  are  common 
seats  of  fracture,  a  frequent  cause  of  which  is  the  use 
of  sharp  curved  bits;  but  rough  usage  by  the  rider  or 
driver  will  now  and  then  cause  fractures  even  with  a 
smooth  bit.  As  a  rule,  at  first,  the  gums  only  are 
affected;  but  in  a  short  time  the  periosteum  and  bone 
are  reached.  Prof  Varnell  says :  '•  If  the  matter  that 
escapes  be  of  a  grayish-brown  color  and  fetid,  it  will 
indicate  disease  of  the  bone ;  but  if  it  is  from  a  sub- 
cutaneous abscess,  the  discharge  will  be  simply  of  a 
purulent  nature,  and  a  speedy  cure  may  be  effected  by 
the  application  of  very  simple  remedies." 


SUnaEOX  FLEMING'S  DISCOVERT.  195 

When  a  fracture  has  been  produced,  inflammation 
and  fetor  will  follow,  and  the  horse  loses  his  appetite. 
If  the  bone  is  removed  and  the  horse  is  allowed  to  rest 
for  a  few  days,  tne  wound  will  heal;  otherwise  the 
most  serious  consequences  may  follow.  The  removal 
of  the  bone  may  be  effected  sometimes  soon  after  the 
fracture;  but  if,  after  cutting  into  the  gum,  it  be  found 
too  firmly  attached  to  the  surrounding  parts,  it  is  bet- 
ter to  wait  a  week  or  two  that  nature  may  loosen  it. 
Bones  an  inch  or  more  in  length  are  often  removed. 
Thus  that  which  at  first  appears  to  be  "only  a  sore 
mouth,"  may,  if  neglected,  pi'ove  the  ruin  of  a  valuable 
horse. 

Fractures  are  often  caused  by  external  violence.  A 
severe  blow,  accidental  or  otherwise,  in  the  region  of 
the  roots  of  the  teeth  may  cause  a  fracture  that  will 
necessitate  the  removal  of  botli  the  bone  and  the  teeth. 

"The  lower  jaw^,"  says  Prof.  Youatt,  "is  more  sub- 
ject to  fracture  than  the  upper,  particularly  at  the 
point  between  the  tushes  and  the  incisor  teeth,  and  at 
the  symphysis  (of  the  chin)  between  the  two  branches 
of  the  jaw.  Its  position,  length,  and  the  small  quan- 
tity of  muscle  covering  it,  especially  anteriorly,  render 
it  liable  to  fracture.  The  same  circumstances,  how- 
ever, combine  to  render  a  reunion  of  the  parts  easy.'' 

The  following  extraordinary  case  of  accidental  frac- 
ture is  reported  by  Surgeon  George  Fleming  ("  Veteri- 
narian," 1874,  p.  094) : 

"  In  18G5,  while  stationed  near  Aldershot,  I  was 
driving  one  day  in  the  neighborhood  of  Farnborough, 
when,  in  a  narrow  lane,  our  progress  was  somewhat 
checked  by  a  ftirmer's  wagon  in  front,  which  compelled 
us  to  travel  at  a  walking  pace  for  some  distance.    Dur- 


196  FEACTUEED   JAWS. 

ing  this  delay  my  attention  was  attracted  to  the  shaft 
horse,  which  had  an  enormous  tumor  on  tiie  right  side 
of  its  face.  It  had  such  a^  singakir  appearance  that  I 
dismounted  from  the  carriage  and  induced  the  driver 
of  the  wagon  to  halt,  when  I  inquired  into  the  history 
of  the  case,  and  made  an  inspection  of  the  tumor.  It 
was  as  large  as  half  a  good-sized  cocounut,  occupied 
nearly  the  whole  side  of  the  face,  and  was  literally 
a  mass  of  what  at  first  appeared  to  be  fragments  of 
hone,  hut  which,  on  a  closer  examination,  proved  to 
be  imperfectly  developed  grinder  teeth.  The  tumor 
looked  as  if  it  were  composed  entirely  of  them.  I  was 
informed  tliat,  when  two  years  old,  tlie  foal  had  taken 
fright  and  ran  away,  and  in  trying  to  get  through  a 
gate,  a  wooden  stump  ran  into  its  face,  making  a  large 
hole.  The  hole  filled  up,  the  tumor  gradually  formed 
on  it,  and  since  that  time  these  'bits  of  bone,'  as  the 
wagoner  called  them,  were  constantly  shed  from  its 
surface.  The  growth  w^as  so  large  that  the  collar  avos 
passed  over  the  head  wdth  great  difficulty.  I  was  so 
mu(;h  interested  in  the  case  that  I  offered  to  keep  the 
animal  while  tiie  removal  of  the  tumor  was  attempted; 
hut  the  farmer  could  not  spare  it  from  w^ork  at  the 
time,  and  I  did  not  have  another  opportunity.'' 

The  following  accounts  of  cases  of  fractured  jaws 
treated  by  various  surgeons  are  from  Prof.  Youatt's 
work,  '^The  Horse"  (p.  445): 

*•  Surgeon  Cartwright  had  a  mare  in  which  the  up- 
per jawbone  was  fractured  by  a  kick  at  the  point 
where  it  unites  with  the  lachrymal  and  malar  bones. 
He  applied  the  trephine,  and  removed  many  small 
bones.  The  wound  Avas  then  covered  by  adhesive 
plaster,  and  in  a  month  the  parts  vv^ere  healed. 


MM.   REVEL   AND   BOULEY'S   SKILL.  197 

^'  Surgeon  Claywortli  reports  the  case  of  a  mare  that 
fell  while  being  ridden  almost  at  full  speed,  and  frac- 
tured the  upper  jaw  three  inches  above  the  corner  in- 
cisors. The  teeth  and  jaw  were  turned,  like  a  hook, 
completely  within  the  lower  teeth.  The  mare  was  cast, 
a  balling-iron  put  into  her  mouth,  and  the  teeth  and 
jaw  puUed  back  to  their  natural  position;  she  was  then 
tied  so  that  she  could  not  rub  her  muzzle  against  any- 
thing, and  was  fed  with  bean-meal  and  linseed  tea. 
Much  inflammation  ensued,  but  it  gradually  subsided, 
and  at  the  expiration  of  the  sixth  week  the  mouth  was 
healed,  scarcely  a  vestige  of  the  fracture  remaining. 

"  An  account  of  a  very  extraordinary  fracture  of  the 
superior  maxillary  bone  is  given  in  the  records  of  the 
Royal  and  Central  Society  of  Agriculture  in  France. 
A  horse  was  kicked  by  another  horse,  fracturing  the 
upper  part  of  the  superior  maxillary  and  zygomatic 
bones,  and  almost  forcing  the  eye  out  of  its  socket. 
Few  men  would  have  dared  to  undertake  a  case  like 
this,  but  Monsieur  Kevel  shrank  not  from  his  duty. 
He  removed  several  small  bones,  replaced  the  larger 
ones,  returned  the  eye  to  its  socket,  confined  the  parts 
with  sutures,  slung  the  horse,  and  in  six  weeks  he  was 
well. 

"Surgeon  Blaine  relates  that  in  treating  a  fracture 
of  the  lower  jaw  he  succeeded  by  incasing  the  entire 
jaw  in  a  strong  leather  frame.  I  have  myself  effected 
the  same  object  by  similar  means. 

"  Prof.  Bouley  says  ("  Recueil  de  Medicine  Veteri- 
naire,"  1838)  that  he  treated  a  horse  whose  lower  jaw 
had  been  completely  broken  off  at  the  neck — that  is, 
at  the  point  between  the  tushes  and  the  corner  incisor 
teeth,  the  detached  bone  being  held  by  the  membrane 
of  the  mouth. 


198  FRACTtJRED   JAWS. 

'•The  horse  was  cast,  the  corner  tooth  on  the  left 
side  extracted,  the  wound  thoroughly  cleansed,  and 
the  fractured  bones  brought  in  contact.  Holes  were 
drilled  between  the  tushes  and  the  second  incisors  of 
both  jaws,  through  which  brass  wires  were  passed.  A 
compress  of  tow  and  a  ligature,  the  bearing-place  of 
the  latter  being  over  the  tushes,  surrounded  the  whole. 
Thus  the  jaws  were  apparently  fixed  immovably  to- 
gether. The  wires  yielded  somewhat  to  the  struggles 
of  the  horse,  but  the  bandage  of  tow  was  tightened  so 
as  to  retain  the  fractured  edges  in  apposition. 

"The  wound  now  began  to  exhale  an  infectious  odor, 
and  gangrene  was  evidei:»tly  approaching.  M.  Bouley 
determined  to  amputate  the  fractured  portion  of  the 
jaw,  its  union  to  the  main  bone  being  apparently  im- 
possible. The  sphacelated  portion  of  the  jaw  was  en- 
tirely removed ;  every  fragment  of  bone  that  had  an 
oblique  direction  was  sawn  away,  and  the  rough  por- 
tions which  the  saw  could  not  reach  were  rasped  off. 

"Before  night  the  horse  had  recovered  his  natural 
spirits,  and  was  reaching  for  something  to  eat.  On  the 
following  day  he  ate  oats,  and  no  one  looking  afhim 
would  have  suspected  that  he  had  been  deprived  of  his 
lov/er  incisor  teeth.  The  next  day  he  ate  hay.  In  a 
fortnight  the  wound  was  nearly  healed." 

C.  D.  House,  veterinary  dentist,  performed  an  unu- 
sual operation  on  a  seven-year-old  horse,  the  property 
of  Mr.  J.  T.  Allen,  of  Hartford,  Conn.  In  187G  a 
surgeon  (?)  made  an  incision  in  the  right  cheek  and 
hnocked  out  a  large  part  of  the  fifth  upper  grinder. 
The  violence  of  the  operation  fractured  botli  the  tooth 
and  the  jaw,  imbedding  a  large  fragment  of  the  former 
in  the  bone  above  the  socket     A  year  afterward,  the 


SKILL  VERSUS   BRUTALITY.  199 


horse  still  suffering  and  discharging  matter  from  the 
nostril,  Mr.  House  was  requested  by  Mr.  Allen  to  ex- 
amine and  if  possible  cure  him.  He  failed,  however, 
to  discover  the  cause  of  the  discharge,  and  it  was  not 
till  the  expiration  of  anotlier  year  that  he  determined 
to  probe  the  case  to  the  bottom,  the  horse  in  the  mean- 
time having  suffered  as  usual.  Making  an  instrument 
of  the  proper  size  and  shape,  he  introduced  it  into  the 
nostril,  seized  the  tooth  fragment  and  drew  it  forth, 
the  horse  at  that  instant  malving  a  deep  expiration, 
which  blew  out  several  fragments  of  bone  and  a  part 
of  the  root  of  the  tooth.  The  animal  made  a  good 
recovery.'^ 

*  The  Worcester,  Mass.,  Sp7j  for  July  13,  1877,  says:  "C  D. 
House  vetsrinarv  dentist,  was  in  the  city  yesterday,  operating 
on  the  horses  of  the  Hamblctouian  Breeding  Stud.  A  case  was 
found  where  the  grinders  had  been  worn  rough,  and  were  be- 
sides slightly  displaced,  so  that  the  horse  in  eating  lacerated  the 
lining  of  the  cheek.  Another  case  was  where  a  colt's  temporary 
tooth"^  after  being  partially  forced  from  its  place  by  the  perma- 
nent, had  remained  fastened  by  one  root,  and  in  such  a  position 
as  to  injure  the  gum  while  the  animal  was  feeding  ;  and  yet  so 
nicely  had  the  decaying  tooth  been  lodged,  that  its  presence  was 
only  detected  by  the  offensive  odor.  Several  cases  of  inflamma- 
tion of  the  gums  were  found,  which  were  accounted  for  by  the 
presence  of  tartar.     The  tartar  was  removed. 

"  Mr.  House's  mode  of  operating  is  unique.  He  uses  no  gag, 
and  the  animal  stands  free.  He  passes  his  hands  over  the  teeth 
of  the  most  vicious  horses,  and  was  never  yet  bitten.     He  has 

Note.— In  a  para.ijraph  of  the  above  note  that  appeared  in  the  first  edi- 
tion of  this  work,  Dr.  House,  who  now  holds  a  diploma,  advertised  the 
importance  of  dentistry  by  depreciating  the  importance  of  that  great 
scourge  glanders,  which  Surgeon  Fleming  describes  (1882)  as  a  most  repul- 
sive, highly  contagious,  and  incurable  nwlady,  very  communicable  between 
the  horse  and  ass  species,  less  so  between  these  and  other  species,  man 
also  being  frequently  infected.  Dr.  Fleming  says  the  disease  was  very 
prevalent  in  London  in  the  winter  of  1882. 


200  FRACTURED  JAWS. 

Surgeon  J.  P.  Heatli  thus  describes  a  case  of  frac- 
tured jaw  ("  Veteriuariau/'  1878,  p.  288): 

"In  May  last  I  was  called  to  see  a  horse  that  had 
been  kicked  by  another  horse.  I  found  a  transverse 
fracture  of  the  left  side  of  the  lower  jaw,  between  the 
first  and  second  grinders,  with  lesion  of  the  buccal 
membrane.  The  bone  protruded  inward,  the  tongue 
hung  out  of  the  mouth,  and  a  constant  flow  of  saliva 
existed.  The  animal's  appetite  was  good,  but  there 
was  of  course  a  total  inability  to  masticate.  The  liorse 
was  seventeen  years  old,  but  as  the  farmer  (Mr.  Gale, 
of  Exnnnster,  Devon,)  could  ill  aliord  his  loss,  I  agreed 
to  try  to  cure  him. 

"  I  procured  a  wedge-shaped  piece  of  wood,  six  or 
•  seven  inches  long  by  half  an  inch  thick,  which,  after 
fitting  it  between  the  branches  of  the  jaw,  I  well  be- 
smeared with  warm  pitch  and  pressed  it  tightly  be- 
tween the  fractured  end  of  the  bone.  I  then  fixed 
another  piece  of  wood  of  the  same  length,  but  two 
inches  thick,  which  was  also  besmeared  with  pitch, 
outside  the  fracture,  placing  a  bandage  six  inches  wide 
over  the  whole,  and  tying  it  over  the  face  below  the 
eyes. 

operated  on  Edward  Everett,  Jud^e  Fullerton,  Emperor  (owned 
by  S.  D.  Houghton,  of  this  city),  and  other  notoriously  vicious 
horses." 

The  statement  about  Mr.  House's  mode  of  operating  is  strictly 
true.  His  control  of  a  horse  appears  to  be  a  gift.  He  never 
confines  a  horse,  not  even  in  performinof  the  operation  of  castra- 
tion. In  an  "  interview"  with  a  reporter  of  The  New  York  Smiy 
printed  in  1877,  in  reply  to  the  question,  "  How  do  you  know 
when  a  horso  has  tlie  toothache  ?"  he  snid  :  "  He  telh  me  that  lie 
has  it."  So  Mr.  House  must  understand  " horse-talk"  as  well  as 
horse-dentistrv. 


SURGEON    HEATH'S  SKILL.  201 

"For  the  first  fortiiiglit  I  do  not  think  the  animal 
took  more  than  a  gallon  of  the  thin  mashes  and  gruel 
with  which  he  was  supplied ;  but  after  that  time  the 
use  of  the  muscles  of  the  tongue  began  to  return,  and 
he  was  able  to  swallow  a  little.  In  about  three  weeks 
he  could  lick  up  oatmeal  and  oilcake  gruel  made  thick, 
and  in  less  than  a  month  I  removed  the  bandage  (al- 
though the  sphnts  remained  for  six  weeks),  as  by  this 
time  he  could  swallow  a  little  pulped  mangold  grass, 
cut  into  chaff.  For  nine  weeks  he  could  only  feed  on 
cut  fodder,  when  he  w^as  turned  out  to  grass.  At  the 
present  time  he  is  in  perfect  health,  feeding  on  ordi- 
nary diet  and  working  constantly.  The  first  and  sec- 
ond grinders,  which  were  loosened,  appear  now  to  be 
as  firmly  fixed  as  the  others." 

The  editor  of  "The  Veterinarian"  reports  the  case 
of  a  pony  that  came  near  starving  from  having  a  stick 
fastened  in  its  mouth.  Xo  fracture  of  the  bone  was 
produced,  but  the  account  of  the  case  is  worthy  of  in- 
sertion here  notwithstanding  that  fact,  for  it  illustrates 
a  class  of  mishaps  to  which  the  horse  is  subject.  He 
says  ("Veterinarian,"  1855,  p.  330): 

"A  pony  was  turned  into  a  pasture,  and  was  not 
seen  for  several  days.  The  owner  found  it  standing  in 
a  corner  of  the  field,  looking  dejected  and  thin,  with  a  ^ 
small  quantity  of  viscid  saliva  escaping  from  its  mouth. 
He  took  care  of  the  pony  for  a  few  days,  during  w^hich 
time  it  took  nothing  but  a  little  water,  which  it  drank 
with  great  difficulty.  Our  attendance  was  now  re- 
quested. Examination  disclosed  a  stick  about  the  size 
of  one's  finger,  firmly  w^edged  across  the  palate,  be- 
tween the  corner  incisors.     Its  pressure  had  produced 


202  TREATMENT   FOB   ABRASED  GUMS. 

extensive  sloughing,  so  tliat  the  bone  was  completely 
exposed.  The  pain  was  so  great  that  the  poor  animal 
stoutly  resisted  our  efforts  to  remove  the  cause  of  its 
suffering.  This,  however,  was  soon  done,  and  the  parts 
being  cleaned  with  tepid  water,  were  afterward  dressed 
with  Tinct.  Myrrhs.  Little  after  treatment  was  nec- 
essary beyond  the  daily  application  of  the  tincture,  a 
mash  diet,  and  the  substitution  of-  oatmeal  gruel  for 
plain  water." 


CHAPTER    XI. 

THE   TEETH   AS   INDICATORS   OF  AGE. 

Their  various  ways  of  Indicating  Age.-The  "Mark's"  Twofold 
[jse.-The  Dentinal  Star.-Marks  witli  too  mucli  Cement.— 
Tricks  of  the  Trade.  -Crib-biting.— Signs  of  Age  ludepend- 
ent  of  tlie  Teeth. 

The  incisor  teetli  of  the  horse,  which,  as  before  said, 
differ  '-'froiii  those  of  all  other  animals  by  the  fold  of 
enamel  which  penetrates  the  body  of  the  crown,  from 
its  broad,  flat  summit,  like  the  inverted  finger  of  a 
glove,"  indicate  age  (1)  by  then-  cutting;  (2)  by  their 
growth;  (3)  by  their  shedding ;  (4)  by  their  marks;* 
(5)  by  their  change  of  shape;  (6)  by  their  change  of 
color;  (7)  by  theh-  length,  and  (8)  by  the  degree  of 
their  outward  inclination.  The  cutting,  growth,  and 
shedding  (of  the  tushes  and  grinders  as  well  as  the  in- 
eisors— the  cutting  and  shedding  occurring  at  com- 
paratively regular  periods,  and  the  growth  being  grad- 
ual), indicate  age  from  birth  till  about  the  sixth  year; 
the  marks  of  the  lower  incisors  from  the  sixth  month 
till  the  eighth  year;  those  of  the  upper  incisors,  though 

*  Prof.  C.  S.  Tomes  says  "the  mark  exists  in  Hipparion,  but 
not  in  the  earlier  progenitors  of  the  liorse."  Prof.  O.  C.  Marsh 
says :  "  The  large  canines  of  Orohipous  became  gradually  re- 
duced in  the  later  genera,  and  the  characteristic  mark  of  the 
incisors  is  found  only  in  the  later  forms." 


204 


THE  TEETH   AS  IXJ)ICATOIlS   OF   AGE. 


perhaps  less  reliable,  during  the  same  period,  and  for 
about  four  or  live  years  longer  (say  the  twelfth  or  thir- 
teenth), and  the  change  in  shape,*  color,  and  position 
from  about  the  seventh  year  till  old  age.  The  change 
in  the  shape  of  tiie  teeth  is  caused  by  their  wear  and 
growth,  the  wear  counteracting  the  growth  and  the 
growth  the  wear. 

In  foals  and  young  horses  the  marks  are  proba'oly 
the  surest  guides  by  which  to  judge  of  the  age.  One 
peculiarity  of  them  is  that,  as  the  teeth  wear  down, 
they  approach  the  posterior  edge.  Besides  their  utility 
in  indicating  age — being  composed  of  enamel  (the  ad- 
amantine substance) — they  greatly  enhance  the  dura- 
bility of  the  teeth— that  is,  during  the  first  third  of 
the  horse's  life.  As  a  rule  the  variations  in  the  size 
and  appearance  of  the  mark  will  be 
as  follows : 

At  six  months  they  are  oblong  and 
distinct  in  the  centrals,  and  the 
cavities  are  plain  in  the  dividers. 

At  one  year  they  are  short  in  the 
centrals,  are  becoming  so  in  the  di- 
viders, but  are  large  in  the  corners. 
At  a  year  and  a  half  they  are  rep- 
resented by  a  small  spot  in  the  cen- 
trals, are  diminished  in  the  dividers, 
but  are  still  large  in  the  corners. 

At  two  years  they  are  no  longer 

visible  in  the  centrals  (in  some  cases 

are   even   shed)  ;    are   smaller    and 

rounder   in    the  dividers,  but   still 

TheMark.-Zmmn^.    phxiu  in  the  corners. 

*  Surg.  Cherry  says  the  sliapo  and  general  character  of  the 
teeth  are  better  criterions  of  age  than  the  marks. 


WUAT  MAY    PUZZLE  A   S'OyiCE.  205 

At  two  years  and  a  half  the  centrals  are  shed ;  the 
marks  are  faint  in  the  dividers,  but  are  distinct  in  the 
corners. 

At  three  years  the  permanent  centrals  are  nearly 
grown ;  the  marks  in  the  dividers  are  just  visible,  and 
have  become  smaller  in  the  corners. 

At  three  years  and  a  half  the  marks  in  the  centrals 
are  long  and  very  distinct;  the  dividers  are  shed,  and 
the  marks  in  the  corners  are  faint. 

At  four  years  tlie  marks  in  the  centrals  show  the 
effects  of  wear,  but  are  still  long  and  distinct ;  the  per- 
manent dividers  are  about  grown,  and  tlie  marks  in 
the  corner  teeth  have  almost  disappeared. 

At  four  years  and  a  half  the  marks  in  the  centrals 
are  still  distinct,  wiiile  those  of  the  dividers  are  at 
their  best.  The  contrast  between  the  large  permanent 
incisors  and  the  small  temporary  corner  teeth,  which 
have  lost  their  marks,  is  striking  at  this  age. 

At  five  years  the  marks  in  the  centrals  are  getting 
smaller  and  rounder,  bnt  are  large  and  distinct  in  the 
dividers ;  the  corners  are  usually  shed  at  this  age. 

"At  six  years,"  says  Prof.  Youatt,  "the  marks  of 
the  central  nippers  are  worn  out.  There  will,  however, 
still  be  a  difference  of  color  in  the  center  of  the  tooth. 
The  cement  filling  the  hole  made  by  the  dipping  of 
the  enamel  will  present  a  browner  hue  than  the  other 
part  of  the  tooth.  It  will  be  distinctly  surrounded  by 
an  edge  of  enamel,  and  there  will  remain  even  a  little 
depression  in  the  center,  and  also  around  the  case  of 
enamel ;  but  the  deep  holes  in  the  center  of  the  teeth, 
with  the  blackened  surface  which  they  present,  and 
also  the  elevated  edge  of  enamel,  will  have  disappeared. 
Persons  little  accustomed  to  horses  are  often  puzzled 
here.     They  expect  to  find  a  plain  surface  of  uniform 


$06 


THE  TEETH  AS  INDICATORS   OF   AGE. 


color,  and  know  not  what  conclusion  to  draw  when 
they  see  both  discoloration  and  irregularity."  The 
marks  in  tlie  dividers  are  much  reduced  in  size,  but 
those  of  the  corner  teeth  are  large  and  distinct. 

At  seven  vears  the  marks  disappear  from  the  divider 


incisors,  an 


d  at  eight  from  the  corner  teeth. 


Monsieur  Girard  thus  describes  the  changes  in  shape 
of  the  incisors,  referring  also  to  the  disappearance  of 
the  marks  in  the  upper  teeth : 

"At  nine  the  central  incisors  become  rounded,  the 
dividers  oval,  and  the  corner  teeth  narrower.    The  cen- 
tral  enamel    (mark)   diminishes    and 
approaches  the  posterior  edge. 

"'At  ten  the  dividers  are  rounder, 
and  the  central  enamel  is  very  near 
the  posterior  edge  and  rounded ;  at 
eleven  they  have  become  roimded,  and 
the  enamel  has  disappeared. 

*-At  twelve  the  comer  teeth  are 
rounded.  The  yellow  band  is  larger, 
and  occupies  the  center  of  the  wear- 
ing surface. 

"At  thirteen  all  the  lower  incisors 
are  rounder;  the  sides  of  the  centrals 
are  becoming  longer.  The  central 
enamel  remains  in  the  upper  corner 
teeth,  but  is  round  and  approaching 
the  posterior  edge. 

"At  fourteen  the  lower  central  in- 
cisors have  a  triangular  appearance; 
the  dividers  are  becoming  long  at  their  sides. 

"At  fifteen  the  central  incisors  are  triangular,  and 
the  dividers  are  becoming  so. 


The  form?  successive- 
ly assiiniid  liv  ihe  dental 
table  of  a'l  illci^ol■  in  con- 
sequence of  fiijtion.— ^. 
Chauireaii. 


CAUSE  OF  THE  YELLOW   COLOR.  '207 

"At  sixteen  the  dividers  are  triangular,  and  the  cor- 
ner teeth  are  becoming  so. 

'^  At  seventeen  the  corner  teeth,  like  the  dividers  and 
centrals,  have  become  triangular,  the  sides  of  the  tri- 
angles being  equal 

"At  eighteen  the  lateral  portions  of  the  triangles 
leno-then  in  succession — first  in  the  centrals,  next  in 
the  dividers,  and  then  in  the  corners;  so  that  at  nine- 
teen the  lower  centrals  are  flattened  from  one  side  to 
the  other;  at  twenty  the  dividers  are  flattened,  and  at 
twenty-one  the  corners  also  are.'' 

The  three  following  extracts  give  some  idea  of  the 
difficulties  to  be  encountered  in  judging  the  age  by 
the  teeth.     Prof,  Youatt  says: 

"Stabled  horses  have  the  marks  sooner  worn  out 
than  those  at  grass,  and  a  'crib-biter'  may  deceive  the 
beat  judge  by  one  or  two  years.  At  eleven  or  twelve 
the  lower  nippers  change  their  original  npright  posi- 
tion and  project  forward.  They  become  of  a  yellow 
color,  the  cause  of  which  is  that  the  teeth  grow  to 
offset  their  wear;  but  the  enamel  which  covered  their 
surface  when  they  were  young  cannot  be  repaired,  and 
that  which  wears  this  yellow  color  in  old  age  is  the 
part  which  was  formerly  in  the  sockets.  The  gums 
recede  and  waste  away,  and  the  tushes  wear  to  stumps 
and  project  outward.''' 

Surgeon  Ewd.  Mayhew  says  ("The  Horse's  Mouth: 
Showing  the  Age  by  the  Teeth'") : 

"That  the  teeth  of  the  horse  denote  age  appears  to 
have  been  a  very  ancient  belief,  which  the  experience 
of  centuries  has  not  changed.     Within  certain  limits 


208  THE  TEETH   AS   IXDICATOKlS   OF  AGE. 

the  belief  is  well  founded,  for  perhaps  no  development 
is  more  regular  than  the  teeth  of  the  horse,  and  no 
natural  process  so  little  exposed  to  the  distortions  of 
artifice.  We  are,  nevertheless,  not  to  expect  that  the 
animal  carries  in  its  mouth  a  certificate  of  birth,  writ- 
ten in  characters  so  deep  that  they  cannot  be  obliter- 
ated or  misinterpreted.  He  who  would  judge  of  the 
age  by  the  teeth  must  study  them,  and  be  prepared  to 
eucounter  difficulties.  In  proportion  as  he  has  done 
the  one,  and  is  enabled  thereby  to  overcome  the  other, 
will  be  his  success.  The  qualified  judge  alone  will 
read  the  teeth  correctly.  He  will  make  allowance 
where  certain  marks  are  indistinct  or  absent,  and  he 
will  be  cautious  in  pronouncing  an  opinion.  The  vet- 
erinary practitioner  knows  that  the  teeth  are  worthy 
of  attention,  and  he  feels  tliat  their  indications,  scien- 
tifically interpreted,  will  seldom  mislead." 

Surgeon  J.  H.  Walsh,  in  his  excellent  work,  "  The 
Horse;  in  the  Stable  and  in  the  Field,"  says: 

"In  order  to  be  able  to  estimate  the  age  of  the  horse 
by  his  teeth,  it  is  necessary  to  ascertain,  as  nearly  as 
may  be,  the  exact  time  at  which  he  puts  up  his  milk 
teeth,  and  also  the  periods  at  which  they  were  replaced 
by  the  permanent.  Finally  it  becomes  the  province 
of  the  veterinarian  to  lay  down  rules  for  ascertaining 
the  age  from  the  degree  of  attrition  which  the  perma- 
nent teeth  have  undergone.  For  these  several  purposes 
the  horse's  mouth  must  be  studied  from  the  earliest 
period  of  his  life  up  to  old  age." 

Judging  the  age  by  the  teeth  is  even  more  compli- 
cated and  difficult  than  is  shown  by  the  foregoing  ex- 
tracts. Among  other  complications  worthy  of  consid- 
eration are  the  following: 


LIKE   CREEDMOOR   MARKS,    HARD  TO   HIT.        209 

About  the  ninth  year  a  mark,  which  is  sometimes 
mistaken  for  the  infundibiihim,  appears  on  tlie  central 
incisors.  Girard  named  it  the  dentinal'''' 
sta7\  but  it  is  also  called  the  fang-hole 
and  secondary  mark.  Dentinal  star  is 
perhaps  the  most  proper  name,  for  the 
mark  is  "  due  to  the  i)resence  of  second- 
ary dentine,  into  which  the  remains  of 
the  pulp  has  been  converted."  The  con- 
version of  the  pulp  into  dentine  prevents 
the  cavity  from  becoming  a  reservoir  for  food,  for 
otherwise  it  would  become  such  as  soon  as  reached  by 
wear ;  and  it  preserves  tlie  tooth  from  decay,  afford- 
ing a  good  illustration  of  Nature  barricading  disease. 
The  pulp  cavity  is  lined  with  dentine  ;  the  dentine 
into  which  the  pulp  is  converted  is  sometimes  called 
osteodentine,  and  may  be  distinguished  from  the  for- 
mer by  its  yellow  tint.  The  star  may  not  afford  reli- 
able data  by  which  to  judge  of  the  age,  but  its  pres- 
ence is  prima  facie  evidence  that  the  tooth  has  been 
worn  to  the  original  pulp  cavity,  f  It  becomes  plainer 
as  it  approaches  the  cavity's  center,  but  the  bottom 
of  the  cavity  is  ultimately  reached,  which  of  course  is 
hollow.  It  is  visible  8  or  10  years,  the  depth  of  the 
cavities  varying  from  about  |  to  1  inch. 

The  marks  of  some  teeth  are  disproportionately 
composed  of  cement,  a  fact  Prof,  A.  Chauveau  says  he 
is  not  aware  has  ever  been  taken  into  account  in  ^^  cal- 

*  See  note,  pag^  viii. 

f  Nature  fills  the  cavity  in  proportion  as  the  crown  is  worn. 
Take  two  teeth  of  tlie  same  kind,  one  just  full-grown,  the 
other  worn  almost  to  its  neck.  In  the  latter  the  spot  is  visible, 
and  if  as  much  material  is  cut  from  the  former  as  has  been  woru 
from  the  latter,  its  cavity  will  be  cat  through,— JcA?i  Hunter. 


210  THE  TEETH   AS   INDICATORS   OF  AGE. 

culatiug  the  progress  of  wear."  Such  teeth  would  soon 
wear  out,  for  there  is  as  much  differeuce  in  the  density 
of  cement  aud  enamel  as  between  cartilage  and  bone. 

The  obliteration  of  the  mark  may  be  hastened  in  a 
small  or  medium-sized  tooth  by  the  friction  of  one  that 
is  abnormally  large,  while  a  stunted  or  dead  tooth  may 
never  lose  its  mark. 

The  more  upright  the  teeth  the  faster  they  wear.  It 
is  said  that  the  crowns  will  be  worn  to  the  extent  of  a 
quarter  of  an  iucli  between  the  fifth  and  sixth  years 
(when  thoy  are  most  upright),  while  only  about  that 
quantity  of  material  vrill  wear  away  between  the  twen- 
tieth and  twenty-fifth  years. 

A  horse's  food  is  a  matter  also  to  be  taken  into  ac- 
count. The  mastication  of  grass,  carrots,  turnips, 
potatoes,  bread,  &c.,  does  not  cause  much  wear  to  the 
teeth.  However,  when  grass  is  procured  by  grazing, 
the  incisors  suffer  mucli  friction — caused,  not  by  the 
grass,  but  by  the  teeth  grinding  one  another,  for  they 
meet  edge  to  edge,  and  are  employed  in  this  occupa- 
tion for  hours,  whereas  a  "feed"  of  corn  is  shelled  in 
a  few  minutes.  In  the  former  case  the  incisors  suiter 
great  friction;  in  the  latter,  the  grinders.  Again,  it  is 
said  that  "horses  fed  on  salt  marshes,  where  the  sea- 
sand  is  washed  among  the  grass,  or  on  sandy  plains  or 
meadows,  are  affected  by  the  increased  friction  of  their 
teeth."  But  no  matter  how  soft  a  horse's  food  may 
be,  if  he  is  addicted  to  the  yice  called  "'crib-biting," 
his  teeth  may  be  ruined  before  those  of  tlie  corn-fed 
horse  have  even  lost  their  marks. 

Several  trade  tricks  are  also  to  be  noted.  Of  "  bish- 
oping,"  Prof.  Youatt  says : 

"Dishonest  dealers  resort  to  a  method  of  imitating 


youatt's  complimexts  to  bishop.  211 

the  mark  in  the  lower  nippers.  It  is  called  Bisliojying, 
from  the  name  of  the  scoundrel  who  invented  it.  The 
horse  of  eight  or  nine  years  is  thrown,  and  with  an 
engraver's  tool  a  hole  is  dug  in  the  now  almost  plain 
surface  of  the  corner  teeth,  its  shape  resembling  the 
mark  in  those  of  a  seven-year-old  horse.  The  hole  is 
then  burned  with  a  heated  iron,  and  a  permanent 
black  stain  is  left.  The  next  pair  of  nippers  are  some- 
times lightly  touched  also. 

^•' An  unprofessional  man  would  be  easily  deceived  by 
this  fraud,  but  it  cannot  deceive  the  trained  eye  of  the 
horseman.  The  irregular  appearance  of  the  cavity, 
the  diffusion  of  the  bluck  stain  around  the  tushes — 
the  sharp  points  and  concave  inner  surface  of  which 
can  never  be  given  again — the  marks  on  the  upper  nip- 
pers, together  with  the  general  conformation  of  the 
horse,  will  prevent  deception.  Moreover,  in  compar- 
ing the  lower  with  tlie  upper  nippers,  unless  the  oper- 
ator has  performed  on  the  latter  also,  they  will  be 
found  to  be  considerably  more  worn  than  the  lower, 
the  reverse  of  wliich  ought  to  be  the  case.  Occasion- 
ally a  clever  operator  will  burn  all  the  teeth  to  a  prop- 
erly regulated  depth,  and  then  a  practiced  eye  alone 
will  detect  the  imposition."* 

*  Rough  on  the  Russians. — Surgeon  John  C.  Knowlson 
makes  the  following  open  confession  ("  The  Complete  Farrier, 
or  Horse  Doctor,"  p.  150):  "  I  was  hired  by  Anthony  Johnson, 
of  Wincohnlee,  Hail,  as  farrier  to  a  number  of  horses  that  were 
going  to  Moscow,  Russia.  We  had  a  liitla  gray,  seventeen-year- 
old  liors3,  named  Pentum,  whose  mouth  I  bishopHd.  He  passed 
for  six  years  old.  was  the  firsb  lioise  sold,  and  brought  £500, 
Enfrlish  m-ney  !    I  only  mention  this  as  a  caution  to  horsemen." 

Surgeon  Knowlson  could  have  evidently  beaten  the  late  Pres- 
ident Lincoln  in  a  (wooden)  horse  trade. 


212     THE  TEETH  AS  INDICATORS  OF  AGE. 

Of  a  deception  practiced  by  sellers  of  two-year-old 
foals,  namely,  passing  off  an  early  two-year-old  for  a 
late  tliree-year-old,  Prof.  Youait  says: 

"  The  asre  of  all  horses  used  to  be  reckoned  from 
May,  but  some  are  foaled  as  early  as  January.  A  two- 
year-old  foal  of  the  latter  date  may,  if  it  has  been  well 
nursed  and  fed  and  has  had  its  central  nippers  drawn 
(that  three  or  four  months'  time  may  be  gained  in  the 
appearance  of  the  permanent),  be.  sold  at  the  former 
date  for  a  three-year-old.  To  horsemen,  however,  the 
general  form  of  the  animal,  the  little  development  of 
the  forehand,  the  continuance  of  the  mark  in  the  divi- 
der nippers,  its  more  evident  existence  in  the  corner 
ones,  and  some  enlargement  or  irregularity  about  the 
gums,  from  the  violence  used  in  forcing  out  the  teeth, 
are  a  sufficient  security  against  deception/' 

And  again  of  four-year-old  foals: 

"Now,  more  than  at  any  other  time,  wdll  the  dealer 
be  anxious  to  put  an  additional  year  upon  the  animal, 
for  the  difference  in  strength,  utility,  and  value  be- 
tween a  four-year-old  colt  and  a  five-year-old  horse  is 
very  great.  But  the  lack  of  wear  in  the  central  and 
divider  nippers,  the  small  size  of  the  corner  ones,  the 
little  growth  of  the  tushes,  the  low  forehand,  the  leg- 
giness  of  the  colt,  and  the  thickness  and  little  depth  of 
the  mouth,  will  at  once  detect  the  cheat." 

The  following  is  Prof.  Youatt's  description  of  crib- 
biting  and  its  effect  on  the  teeth  ("The  Horse,"  pp. 
511,519): 

"The  horse  lays  hold  of  the  manger  with  his  teeth, 
violently  extends  his  neck,  and  then,  after  some  con- 


COLICKY   ClUB-BITERS.  213 

vnlsive  action  of  the  throat,  a  slight  grunting  is  heard, 
accompanied  by  a  sucking  in  of  an*.  It  is  n^t  an  effort 
at  simple  eructation,  arising  from  indigestion,  but  is 
merely  the  inhalation  of  air.  It  takes  place  with  all 
kinds  of  diet,  and  when  the  stomach  is  empty  as  well 
as  when  it  is  full. 

*'  The  effects  of  crib-biting  are  pkiin  enough.  The 
teeth  are  worn  away  and  occasionally  broken,  and  in 
old  horses  to  a  very  serious  degree.  Sometimes  graz- 
ing is  rendered  difficult  or  almost  impossible.  Corn  is 
often  wasted,  for  the  horse  will  frequently  'crib'  with 
his  mouth  full  of  it,  and  the  greater  part  of  it  will  fall 
over  the  edge  of  the  manger.  Much  saliva  escapes  also, 
which  impairs  digestion.  Crib-biting  horses  are  more 
subject  to  cohc  than  others,  and  to  a  species  difficult 
of  treatment  and  frequently  dangerous. 

''The  only  remedy  is  a  muzzle,  with  bars  across  the 
bottom  sufficiently  wide  to  allow  the  horse  to  pick  np 
his  corn  and  pull  his  hay,  but  not  to  grasp  the  edge  of 
the  manger.  Some  recommend  turning  out  for  five  or 
six  months;  but  this  will  never  succeed  except  with 
young  horses,  and  rarely  with  them.  The  old  crib- 
biter  will  substitute  the  gate  for  the  manger.  We  have 
often  seen  him  galloping  across  the  field  for  the  mere 
object  of  having  a  gripe  at  a  rail." 

Prof  Youatt  further  says  that  the  vice  is  a  species 
of  unsoundness,  having  been  so  decided  in  the  courts. 
It  is  often  the  result,  he  says,  of  imitation,  but  oftener 
the  consequence  of  indigestion.  Mischief,  he  says,  is 
another  cause  of  it. 

The  mouth,  it  is  said,  is  broader  at  seven  years  of 
age  than  at  any  other  time;  but,  so  far  as  judging  the 
age  is  concerned,  this  fact  (assertion)  is  of  little  prac- 


214  THE   TEZTH   AS   I^TDICATORS   OF   A3E. 

tical  U33.     The  facts  that  follow,  however,  are  of  more 
or  leso  use,  and  are  worthy  of  perusal.     Prof.  Youatt 

says : 

''  The  indications  of  age,  independent  of  the  teeth, 
are  deepening  of  the  hollows  over  the  eyes ;  wrinkles 
over  tne  eyes  and  about  the  mouth ;  gray  hairs,  par- 
ticularly over  the  eyes  and  about  the  muzzle;  the 
countenance  and  general  appearance;  thinness  and 
hanging  down  of  the  lips;  sharpness  of  the  withers; 
sinking  of  the  back;  lengthening  of  the  quarters,  and 
the  disappearance  of  windgalls,  spavins,  and  tumors  of 
every  kind.  *  ^  "  At  nine  or  ten  the  *bars' of 
the  mouth  become  less  prominent,  and  their  regular 
diminution  will  indicate  increasing  age." 

Of  another  deception  Prof.  Youatt  says: 

"We  form  some  idea  of  the  age  of  the  horse  by  the 
depth  of  the  pits  above  the  eyes.  There  is  at  the  back 
of  the  eye  a  quantity  of  fatty  substance,  on  which  it 
may  revolve  wichout  friction.  In  aged  horses,  and  in 
diseases  attended  with  general  loss  of  condition,  much 
of  this  disappears.  The  eye  becomes  sunken,  and  the 
pit  above  it  deepens.  Dishonest  dealers  puncture  the 
skin,  and,  with  a  t -/bacco-pipe  or  tube,  blow  into  the 
orifice  till  the  depression  is  almost  filled.  This,  with 
the  aid  of  •bishr)ped'  teeth,  may  deceive  the  unwary. 
The  fraud  may  bo  easily  detected,  however,  by  press- 
ing on  the  part.'' 

"Frank  Fores<-er"  (William  Henry  Herbert),  says 
("The  Horse  of  America,"  vol  i,  p.  72): 

"Much  stress  is  laid  by  many  persons  on  the  depth 
of  the  svipra-orbital  cavities,  and  more  yet  on  the  length 
and  extreme  protrusion  of  the  nippers  beyond  the 


SPAI^ISH   HORSES   AXD   MULES— AXCIEXTS.       215 

gums,  as  also  on  hollowness  of  back.  I  have  seen  colts 
— got  ly  aged  stallions — having  all  these  indications 
of  age  before  they  had  a  full  mouth  ;  and  with  cavities 
and  hollow  backs  before  they  had  got  colt's  teeth." 

Suri^eon  Brandt,  who  thinks  shape  indicates  age  as  well  after 
the  eiglith  year  as  marks  do  before,  says  ("  Age  of  Horses  ") : — 
"  Some  breeds,  the  Spanish  for  instance,  require  a  longer  time 
to  develop  than  others.  The  bones  appear  to  be  harder,  the 
teeth  change  somewhat  later,  and  wear  more  slowly ;  some- 
times, after  the  fifth  year,  they  appear  one  or  two  years  younger 
than  they  are.    The  age  of  crib-biters  can  be  told  by  the  corner 

teeth,  "wllirh  nre  Sftlrlnm  inini'ftd       Slionlrl  tliia  1^*»  ±lifi  <^asis.    lanur 


Pliny  did  not  compile  Yarro  (B.  C.  116)  and 
Columella  (A.  D.  42)  carefully.  Varro  (Book  IL, 
Cap.  YII.)  says  :  "It  is  by  the  teeth  that  they  find 
out  the  age  of  a  horse."  He  then  describes  the 
shedding  of  the  teeth,  concluding  as  follows  :  "Others 
grow  in  their  place,  which,  hollow  at  first,  fill  up  in 
the  sixth  year,"  etc.  The  error  about  the  cavities 
filling  up  stands  to  this  day.  Unlike  the  pulp  cavi- 
ties, they  are  not  filled  by  nature  with  tooth  ma- 
terial ;  they  are  obliterated  by  wear.  Crlumella 
(Book  VI.,  Cap.  XXIX.)  not  only  describes  the 
marks,  but  the  shedding  of  the  molars  also.  In 
Latin  he  says  :  "  Intra  sextum  deinde  annum,  molares 
super  lores  cadunt.'"  So  the  error  of  Aristotle  about 
the  non-shedding  of  the  molars  did  not  stand  till 
the  sixteenth  century.  (See  page  69.)  Palladius 
(about  A.  D.  400)  and  Vegetius  (about  the  same 
time)  describe  both  the  marks  and  the  shedding  of 
the  molars.  Yegetius  speaks  of  the  wrinkles  in  the 
upper  lip,  the  number   of   wrinkles  indicating  the 


4  THE  TE2TH   AS   IXDICATOIIS   OF   ASE. 

•Ill  US-     The  facts  tliat  follow,  however,  are  of  more 
les3  use,  aud  are  worthy  of  perusal.     Prof.  Youatt 

"  The  indications  of  age,  independent  of  the  teeth, 
•e  deepening  of  the  hollows  over  the  eyes ;  wrinkles 
^er  the  eyes  and  about  the  mouth ;  gray  hairs,  par- 
cubrly  over  the  eves  and  about  the  muzzle;  the 
)untenance  and  general  appearance;  thinness  and 
ano-ino-  down  of  the  lips;  sharpness  of  the  withers; 
S\..^nf  the  back;  lengthening  of  the  quarters,  and 


number  of  years,  and  also  the  black  spots  in  the 
middle  of  the  teeth  about  the  twelfth  year.  In  con- 
clusion he  says  :  "Finally,  the  number  of  wrinkles, 
the  sadness  of  the  countenance,  the  stupor  of  the 
eyes,  the  baldness  of  the  eyelids,  the  dejection  of 
the  neck,  and  the  lassitude  of  the  whole  body  indi- 
cate age."  (Book  IV.,  Cap.  V.)  I  have  never  seen 
what  could  be  called  a  description  of  the  wrinkles  in 
any  other  book,  but  my  attention  was  called  to  them 
by  Dr.  Wm.  Wilson,  of  Jersey  City,  N.  J.,  in  1881. 
Vegetius  Kenatus,  Puhlius,  is  often  confounded  with 
Vegetius  Eenatus,  Flavhts,  a  military  author.  Ve- 
getius wrote  on  veterinary  science  ;  Varro,  Columel- 
la and  Palladius  on  agriculture.  Fragments  of  the 
works  of  Apsyrtus  (or  Absyrtus),  the  Greek  veter- 
inarian (about  A.  D.  830),  are  extant,  but  I  have 
never  seen  anything  of  his  on  age.  He  described 
glanders,  fevers,  epizootic  influenza,  dental  cysts, 
etc.  (See  Jouunal  of  Comparaiive  Medicine  and 
Surgery  for  Januarv,  1884,  page  19.) 


SPANISH   HORSES   AKD   MULES— ANCIEXTS.       215 

gums,  as  also  on  bollowness  of  back.  I  have  seen  colts 
— got  ly  aged  stallions— hsLYing  all  these  indications 
of  age  before  tbey  bad  a  full  mouth  ;  and  witli  cavities 
and  hollow  backs  before  tbey  bad  got  colt's  teeth." 

Suri^eon  Brandt,  who  thinks  shape  indicates  age  aa  well  after 
the  eighth  year  as  marks  do  before,  says  ("  Age  of  Horses  ") : — 
"  Some  breeds,  the  Spanish  for  instance,  require  a  longer  time 
to  develop  than  others.  The  bones  appear  to  be  harder,  the 
teeth  change  somewhat  later,  and  wear  more  slowly;  some- 
times, after  the  fifth  year,  they  appear  one  or  two  years  younger 
than  they  are.  The  age  of  crib-bitei^  can  be  told  by  the  corner 
teeth,  which  are  seldom  injured.  Should  this  be  the  case,  liow- 
ever,  add  as  many  lines  as  are  needed  to  make  them  the  natural 
length.  The  horee  is  as  many  years  younger  as  the  teeth  are 
lines  too  short.  The  front  teeth  are  frequently  worn  away 
earlier  when  horses  have  been  fed  on  unshelled  corn. 

•'  The  age  of  mules  cannot  be  ascertained  with  the  same  ac- 
curacy as  that  of  horses.  After  their  eighth  year  they  usually 
appear  younger  than  they  are." 

JVote.—C.¥.  Hoeing.  M.R.C  V.S.  (Jersey  City, N.J.)  sars  the  fact  that  the 
mai'ks  inflicate  age  was  discovered  t>y  Prof.  Pessiaa  of  Vienna  in  1818-29. 

The  ancients  appear  to  have  known  nothing  about  the  marks.  Aristotle 
(His.  Animals,  Bohn's  trans.,  pp.  170  1)  says  that  before  casting  its  teeth  a 
h'orse  has  its  mark,  bu(  not  afterivard.  After  casting  them  age  is  not  easily 
told,  but  is  nsiially  ascertained  by  the  canines,  which  in  riding-horses  are 
generally  bit-wora  ;  these  teeth  are  called  the  marMng  teeth.  (That  is  they 
are  marked  by  wear.    They  have  no  natural  marks.     See  p.  G9.) 

Xenophon,  who  finds  use  for  tushes  in  bridling  a  horse— pressing  the  lip 
agiinst  them— says  that  in  buying  a  horse,  "  Xo  avoid  being  cheate:!,  let  it 
Bot  escape  notice  what  his  age  is ;  if  he  has  not  the  foal  teeth,  he  can  neither 
give  pleasure  with  anticipate:!  exertion  nor  be  easily  disposed  of."  (p.  719.) 

Pliny  says  age  is  indicated  by  the  eruption  and  shedding  of  the  incisors 
(giving  accurate  dates)  ;  then  by  th3  projecting  of  the  teeth,  the  gi-ayness 
of  the  eyebrows,  a.;id  the  depth  of  the  pits  around  them.    (Vol.  iii.  p.  60.) 

Pliny  compiled  from  Van-o,  Columella,  and  many  others.  Would  they 
all  fail  to  mention  the  marks  if  they  knew  anything  about  them  ? 

Erroneous  and  Extraordinary  Statements  by  P'dmj.—Hov^e^''  teeth  grow 
whiter  with  age.  If  a  horse  is  gelded  before  it  changes  its  teeth  it  never 
sheds  them.  No  animal  sheds  the  molars.  Men  have  more  teeth  than 
women.  All  men,  except  the  Turduli,  have  .32  teeth.  Some  persons  have  a 
continuous  bone  in  place  of  teeth.  Human  teeth  contain  venom  ;  they  tar- 
nish a  mirror  and  kill  unfledged  pigeons,    Zocles  had  a  set  of  teeth  at  104. 


CHAPTER    XII. 

THE   TRIGEMINUS   OR   FirXH    PAIR   OF   SERVES. 

Its  Nature  aud  the  Relation  it  "bears  to  tlie  Teeth. — Its  Coui'se  in 
tliG  Horse  and  in  Man. 

The  thread-like  nerves  of  the  teeth  are  derived  from 
the  superior  and  inferior  maxillary  branches  of  the 
trigaminiis  or  hfch  pair  of  nerves.  In  the  horse  thess 
branches  are  four  or  five  times  as  thick  as  a  ribbon 
and  about  five-eighths  of  an  inch  v.'ide.  The  ophthal- 
mic branch  is  smaller  and  shorter,  its  course  extend- 
ing only  from  the  brain  to  the  eye,  while  that  of  the 
two  former  extends  to  the  lips,  running  parallel  to  and 
about  an  inch  from  the  roots  of  the  grinder  teeth.* 

The  description  of  the  trigeminus  and  its  course  is 
from  a  lecture  by  Prof.  Youatt  to  veterinary  students, 
and  may  be  found  in  '-'The  Veterinarian"  for  1834 
(p.  121).  In  the  first  part  of  the  lecture  the  nature  of 
the  trigeminus— its  double  origin  and  function's 
expatiated  upon,  a  summary  of  which  is  that  tlie  sensi- 
tive and  motor  roots,  are  contained  within  the  same 
sheath  ;  that  the  sensitive  root  is  so  mucli  larger  and 
its  fibrils  so  much  more  numerous  than  tlie  motor  that 

*  For  tlie  preparation  of  an  anatomical  specimen  sliowinc;  tlie 
j^eneral  course  of  the  trif^ominns,  I  nm  indebted  to  Prof.  J.  M. 
Heard,  of  the  New  York  College  of  Veterinary  Surgeons. 


THE  TWO   ROOTS.  217 

it  may  still  be  callod  the  sensitive  nerve  of  the  face; 
that  the  trigeminus  is  the  only  nerve  of  the  brain  that 
bestows  sensibility  to  the  face,  except  a  few  branches 
from  the  cervicals,  which  may  be  traced  to  the  lower 
part  of  it ;  that  there  are  some  anatomical  facts  which 
incontestably  prove  that  the  motor  nerve  exists :  that 
Sir  Charles  Bell  laid  the  root  of  the  trigeminus  bare  in 
an  as3  immediately  after  the  animal's  death,  and  that 
on  irritating  the  nerve  the  muscles  of  the  jaw  acted 
and  the  jaw  closed;  that  he  divided  the  root  of  the 
nerve  in  a  living  animal,  and  the  jaw  fell ;  *  that  he 

*"  Re-establishment  of  Sensibflity  after  Resection 
OF  Nerves. — A  memoir  by  MM.  Aiioing  and  Tripier  was  read 
before  the  Frencli  Academy,  November  28th,  on  the  effect  of  re- 
section of  certain  nervous  trunks.  Clinical  facts  have  several 
times  shown  that  after  wounds  which  have  altered  or  destroyed 
a  portion  of  a  nerve,  sensibility  rstiirns  in  the  integuments  to 
which  the  nerve  is  distributed.  MM.  Arloing  and  Tripier  made 
nervous  resections  in  dogs,  and  saw  sensibility  reappear  after  a 
certain  time  in  the  integuments  to  which  the  branches  of  the 
nerve  were  distributed,  and  in  the  peripheral  end  of  the  nerve 
itsolf." — Popular  Science  Reviem,  1SG7. 

"  How  Motor-Nerves  End  in  Non-strtated  Muscular 
Tissue. — A  very  A^aluable  communication  stating  the  results  of 
M.  Henocque's  researches  has  been  published  in  "  TArchives  de 
Physiologie,"  and  may  be  thus  abstracted:  1.  The  distribution 
of  the  nerves  in  smooth  muscle  is  not  only  identical  in  man  and 
other  vertebrate  animals  in  which  it  has  been  observed,  but  is 
essentially  similar  to  all  the  organs  containing  smooth  muscle. 

2.  B?fore  tenninating  in  the  smooth  muscle,  the  nerves  form 
three  distinct  plexuses  or  networks — [n)  a  chief  or  fundamental 
plexus,  containing  numerous  ganglia,  and  situated  outside  the 
smooth  muscle ;  {h)  an  intermediate  plexus  ;  and  (c)  an  intra- 
muscular plexus,  situated  idthin  the  fasciculi  of  smooth  fibers. 

3.  The  terminal  fibrils  are  everywhere  identical.  They  divide 
and  suhdi\'ido  dichotomously,  or  anastomose,  and  terminate  by 
a  slight  swelling  or  knob,  or  in  a  punctiform  manner.    The  ter- 

10 


218  THE   FIFTH   P'AIE  OF   NERVES. 

divided  the  superior  maxillary  branch  on  both  sides, 
the  animal  losing  the  power  of  using  the  lips;  that 
Mr.  Mayo  divided  the  root  of  both  the  superior  and 
inferior  maxillary,  the  result  being  that  the  lips  no 
longer  remained  in  perfect  apposition,  and  the  animal 
ceased  to  use  them  in  taking  up  his  food;  that  the 
sensitive  root,  or  a  portion  of  it,  after  entering  the  cav- 
ernous sinus,  swells  out  into  or  passes  through  a  gan- 
glion, and  that  the  motor  root  can  be  traced  beyond 
the  ganglion,  uniting  afterward  with  its  fellow  and 
forming  the  perfect  nerve;  that  the  ganglion,  being 
composed  of  sensitive  fibrils  only,  resembles  a  brain. 

minal  swelling  appears  to  occupy  different  parts  of  tlie  smootli 
muscular  fiber,  but  most  frequently  to  be  in  the  neighborhood 
of  the  nucleus,  or  at  the  surface  of  the  fibers,  or,  lastly,  between 
them." — The  Monthly  Microscopical  Jouriod,  1S70. 

"Structure  of  Nerves. — M.  Roudanoosky  says  that  the 
primitive  elements  of  nerves  are  tubes  having  a  pentagonal  or 
hexagonal  configuration.  As  to  their  constitution,  he  says  that 
every  nerve  has  a  substratum  of  brain-matter,  and  also  of  the 
spinal  marrow,  and  probably  of  the  ganglionic  matter  also.  The 
gray  matter,  he  says,  is  the  fundamental  nervous  substance,  and 
plays  the  principal  part  in  the  functions." — "  Veterinarian," 
1S65,  p.  313. 

In  a  letter  to  his  brother,  G.  J.  Bell,  written  in  1807,  Sir 
Charles  says :  "  I  consider  the  organs  of  the  outward  senses  as 
forming  a  distinct  class  of  nerves.  I  trace  them  to  corresi^ond- 
ing  ])arts  of  the  brain,  totally  distinct  from  the  origin  of  the 
others.  I  take  five  tubercle  s  within  the  brain  as  the  internal 
ssnses.  I  trace  the  nerves  of  the  nose,  e3'e,  ear,  and  tongue 
to  these.  Here  I  see  established  connection  ;  there,  the  great 
mass  of  the  brain  receives  processes  from  the  central  tubercles. 
Again,  the  great  masses  of  the  cerebrum  send  down  processes 
or  crura,  which  give  off  all  the  common  nerves  of  voluntary  mo- 
tion. I  establish  thus  a  kind  of  circulation,  as  it  were." — Medi- 
cal Gnzcttj. 


THE   COURSE   OF   THE   KERVE.  219 

Prof.  Youatfc's  description  of  the  course  of  the  tri- 
geminus is  as  follows: 

"The  trigeminus  has  been  described  as  springing 
by  a  multitude  of  fdaments  from  the  crura  cere  belli, 
and  forthwitli  running  for  safety  into  the  cavernous 
sinuses,  and  there  suddenly  enlarging  into  or  passing 
through  a  ganglion.  The  nerve,  as  its  name  implies, 
divides  into  three  parts,  the  division  taking  place  in 
the  cavernous  sinus,  after  the  superior  or  sensitive 
root  lias  been  joined  by  the  inferior  or  motor  root. 
Each  part,  before  it  leaves  the  cranium,  assumes  a  dis- 
tinct investment  of  dura  mater.  The  branches  are 
named,  from  the  parts  to  which  tliey  are  destined,  the 
Ophthalmic,  the  Superior  Maxillary,  and  the  Inferior 
Maxillary. 

"The  ophfiiaJmic  is  the  smallest  of  tlie  three.  It  is 
formed  within  the  sinus,  where  it  is  in  conjunction 
with  the  superior  maxillary,  which  it  soon  leaves,  and, 
passing  through  the  foramen  lacerum  into  the  orbit, 
subdivides  and  forms  three  distinct  branches — the 
Supra-orbital  (the  frontal),  the  Lachrymal,  and  the 
Lateral  Nasal  (the  nasal).  The  supra-orbital  climbs 
behind  the  muscles  of  the  eye,  giving  filaments  to  the 
rectus  superior  and  the  superior  oblique,  and  some 
also  to  the  fatty  matter  of  the  eye.  The  main  branch, 
escaping  through  the  superciliary  foramen,  is  soon  lost 
in  ramifications  on  the  elevator  of  the  superior  eyelid, 
the  integument  of  the  forehead,  and  the  periosteum. 
The  lachrymal,  as  its  name  implies,  is  chiefly  concerned 
with  the  laclirymal  gland;  a  few  ramifications,  how- 
ever, are  sent  to  the  conjunctiva  and  also  to  the  ciliary 
glands  of  the  upper  eyelid,  while  a  distinct  twig  of  it 
passes  out  at  the  angle  between  the  zygoma  and  the 


220  THE  FIFTH   PAIR  OF  SERVES. 

frontal  orbital  process,  where  it  anastomoses  with  the 
sapra-orbital  and  with  ramifications  from  the  superior 
maxillary.  It  is  also  lost  on  the  integument  and 
muscles  of  the  forehead.  The  lateral  nasal  is  the 
largest  of  the  three.  Almost  at  its  beginning  we  ob- 
serve the  filaments  that  help  to  form  the  Ophtlialmic 
Ganglion.  They  ar3  more  numerous  and  more  easily 
traced  in  some  of  our  domesticated  animals  than  in 
others,  and  the  ganglion  itself  is  difibrently  developed, 
but  for  what  physiological  purpose  I  know  not.  It  is 
comparatively  larger  in  the  ox  than  in  the  horse,  and 
sends  more  filaments  to  the  iris.  Four  distinct  fila- 
ments may  be  traced  in  the  ox,  but  seldom  more 
than  two  in  the  horse  or  the  dog.  To  these  fila- 
ments others  of  the  ophthalmic,  that  have  not  passed 
through  the  ganglion,  afterward  join  themselves;  so 
that  the  ciliary  are  also  minute  compound  nerves  of 
motion  and  sensation.* 

*  "  The  best  account,  liowev^er,  of  this  is  ^ven  by  Dr.  Jonas 
Quain  ('  Qnain's  Anatomy/  p.  7(>8).  He  considers  the  ganglion 
as  a  center  of  nervous  influence — a  little  brain,  as  it  were — and 
the  filaments  which  some  anatomists  describe  as  composing,  he 
speaks  of  as  branches  given  out  from  it.  '  It  lies,'  says  he, 
'  within  the  orbit,  about  midway  between  the  optic  foramen  and 
the  globe  of  the  eye,  and  is  inclosed  between  the  external  rectus 
muscle  and  the  optic  nerve.  It  is  exceedingly  .small  and,  owing 
to  its  being  imbedded  in  the  soft  adipose  tissue  which  fills  the 
interstices  of  the  different  parts  within  the  orbit,  difficult  to  find. 
Its  branches  are  the  following:  From  its  anterior  border  from 
sixteen  to  twenty  filaments  issue,  which  proceed  forward  to  the 
surface  of  the  sclerotic,  and  pierce  it  through  minute  foramina. 
These  arc  the  ciliary  nerves.  In  their  course  to  the  globe  of  the 
eye  they  are  joined  by  one  or  two  filaments  derived  from  the 
nasal  nerve,  but  they  do  not  form  a  plexus  (an  interlacement). 
They  become,  however,  dispersed  or  divided  into  two  fasciculi, 
one  above  and  the  other  below  the  optic  nerve,  the  latter  being 


THE   OPHTHALMIC   NERVE.  221 

''The  ophthalmic  nerve,  after  running  between  the 
rectus   superior  and  the   retractor   muscles,  gives   a 

the  more  numerous.  They  pass  between  the  choroid  membrane 
and  the  contiguous  sm-face  of  the  sclerotic — lodged  in  grooves  in 
the  latter — and  on  reaching  the  ciliary  lig-ament,  pierce  it,  a  few 
appearing  to  be  lost  in  its  substance,  while  all  the  rest  pass  in- 
ward and  ramify  in  the  iris.  From  the  posterior  border  of  the 
ganglion,  which  seems  as  if  terminated  by  two  angles,  two 
branches  issue,  one  of  which  passes  backward  and  upward  to 
the  nasal  branch  of  the  ophthahnic  nerve,  appearing  to  be  the 
medium  of  communication  between  the  ganglion  and  the  rest  of 
the  ganglial  system,  by  being  prolonged  to  the  carotid  plexus. 
The  other,  the  shorter  branch,  passes  downward  and  backward 
to  the  inferior  oblique  branch  of  the  motor  nerve  of  the  eye.' 

"  For  my  own  part,"  says  Prof.  Youatt,  "  I  am  now  disposed 
to  be  very  much  of  Dr.  Quain's  opinion.  It  was  not  fittin<T  that 
the  motions  of  the  iris  should  be  under  the  control  of  the  will — 
they  should  respond  to  the  varying  intensity  of  the  light." — W. 
Touatt  in  "  Vderinnrian"  for  IS  JO,  p,  49. 

Mons.  Cuvier  says  :  "  It  divides  into  two  ramifications,  one  of 
which  proceeds  toward  the  optic,  unites  with  the  small  branch 
of  the  third  pair,  and  by  this  union  produces  a  nervous  enlarge- 
ment called  the  lenticular  or  ophthalmic  ganglion.  This  jran- 
fflion  usually  sends  off  the  ciliary  nerves,  disposed  in  two  bun- 
dles. They  are  each  composed  of  several  filaments,  which  enter 
the  globe  of  the  eye  obliquely.  The  iris  receives  a  great  num- 
ber of  small  ramifications  from  the  ciliary  nerves,  which,  after 
having  perforated  the  sclerotic  and  passed  around  the  choroides 
longitudinally,  like  ribbons,  but  %vithout  penetrating  it,  are  lost." 
— "  Comparative  Anatomy"  Vol.  II,  p.  306. 

Prof.  W.  Percivall  says:  "  Upon  the  outer  side  of  the  optic 
nerve,  between  it  and  tliat  part  of  the  motor  oculi  from  which 
the  branch  nerves  spring,  is  situated  the  ophthalmic  ganglion. 
This  little  body  is  principally^ constituted  of  branches  from  the 
third  pair,  but  it  receives  a  filament  or  two  from  the  sixth.  The 
nervous  threads  transmitted  by  the  ganglion  surround  the  sheath 
of  the  optic  nerve,  and  pursuing  their  course  over  it,  penetrate 
the  globe  of  the  eye,  and  run  to  be  dispersed  upon  the  iris." — 
"Anatomy  of  the  Horse,"  p.  336. 


222  THE   FIFTH    PAIR   OF   NERVES. 

branch  to  the  ^membrana  nictitaus/  aud  then  takes  a 
singular  course.  Some  ramifications  go  to  the  frontal 
sinuses  and  the  foramina,  and,  piercing  the  orbit  of 
the  eye  for  this  purpose,  present  a  beautiful  view  in 
young  animals,  particularly  the  sheep.  The  main 
branch  then  enters  the  cranium  again  through  the 
internal  orbital  foramen,  passes  under  the  dura  mater, 
returns  through  the  cribriform  plate,  and  ramifies  on 
the  membrane  of  the  nose,  sending  some  branches  as 
low  as  the  false  nostril  and  alae. 

'^  The  superior  riiaxillary  nerve,  or  second  branch  of 
the  trigeminus,  contains  little  that  is  peculiar  to  or 
has  a  practical  tendency  in  quadrupeds.  The  different 
situation  and  conformation  of  the  bones  of  the  face 
cause  the  principal  or  only  variation  in  the  distribu- 
tion of  this  branch  in  the  biped  and  the  quadruped. 
It  leaves  the  cranium  through  the  foramen  rotundum, 
and  at  the  base  of  the  skull  gives  off  small  ramifica- 
tions to  the  inner  canthus  of  the  eye,  the  antrum,  and 
the  two  posterior  grinder  teeth.  It  also  supplies  the 
lateral  portion  of  the  nasal  cavity  through  the  spheno- 
palatine foramen,  while  filaments  are  given  off  from 
the  origin  of  the  trunk  to  the  temporal  muscle.  A 
branch  also  runs  along  the  upper  border  of  the  septum 
nasi  to  the  palate,  and  a  larger  branch,  which  trav- 
erses the  palate  in  company  with  its  blood-vessels, 
passes  through  the  foramen  incisivum  to  "the  upper 
lip.  The  main  trunh  of  the  nerve  now  enters  into  the 
superior  and  exterior  foramen,  in  the  hiatus  between 
the  palatine  bone  and  the  tuberosity  of  the  superior 
maxillary  bone,  leading  into  a  bony  canal  (easily  traced 
in  the  horse)  between  the  maxillary  sinus  and  the  an- 
trum, and  appearing  as  a  great  pillar  passing  tlirough 
the  palatine  sinuses  in  the  ox.     It  traverses  this  canal, 


THE  GOOSE'S  FOOT.  223 

and  at  length  emerges  on  the  face  through  the  fora- 
men infra-orbitariiim,  and  under  the  levator  lahii  supe- 
rioris  muscle.  It  no  sooner  escapes  from  this  canal 
than  it  forms  the  'pes  anserinus'  (the  goose's  foot,  for 
it  divides  something  like  the  foot  of  this  bird).  It 
anastomoses  with  or  receives  numerous  branches  from 
the  seventh  pair,  and  forms  an  intricate  plexus  about 
the  lower  part  of  the  face  and  muzzle.  The  nerves, 
however,  are  wisely  and  beautifully  interwoven,  for  the 
lips,  being  the  seat  of  touch,  require  all  the  flexibility 
and  more  than  the  sensibility  of  the  human  hand. 

"The  inferior  maxillary  nerve,  or  third  branch  of 
the  trigeminus,  emerges  from  the  cranium  through 
the  foramen  lacerum  basis  cranii,  and  very  soon  gives 
of£  four  important  branches.  The  first  branch,  reck- 
oning posteriorly,  proceeds  backward  below  the  con- 
dyle of  the  jaw,  where  it  divides  into  two  portions. 
The  first  runs  up  to  the  parotid  gland,  ramifies  into 
many  filaments,  and  unites  with  the  seventh  pair.  It 
dips  deep  into  and  principally  supplies  the  temporal 
muscle,  and  penetrates  and  is  distributed  through  the 
masseter  muscle.  In  this  division  there  seems  to  be 
concentrated  the  greater  part  of  the  motor  fibrils  of 
the  trigeminus,  for  these  are  muscles  of  extensive  and 
powerful  action.  There  are  few  muscles  of  the  frame 
that  are  oftener  or  more  powerfully  employed  than 
those  concerned  in  mastication ;  but  with  the  motor 
fibrils  those  of  sensation  are  doubtless  conjoined. 

"  The  second  branch  is  a  long  and  slender  one.  It 
first  dips  into  the  pterygoideus  muscle,  which  is  sup- 
plied by  it;  consequently  it  is  here  also  a  motor  as  well 
as  a  sensitive  nerve.  It  then  passes  around  or  behind 
the  tuberosity  of  the  upper  jaw,  supplying  the  bucci- 
nator muscle— possibly  with  sensitive  fibrils  alone,  for 


224  THE  FIFTH   PAIR  OF   NERVES. 

others  go  to  this  muscle  from  the  seventh  pair.  In 
the  buccinator  these  fibrils  are  usually  lost;  but  some- 
times a  few  of  them  may  be  traced  to  the  lower  lip. 

"  The  third  branch,  in  the  order  of  its  being  given 
off,  is  the  dental  nerve.  This  is  generally  considered 
the  continuation  of  the  trunk  of  the  inferior  maxillary 
nerve.  It  passes  across  the  pterygoideus  and  enters  a 
canal  (the  dental  canal),  on  the  inner  face  of  the  lower 
jawbone,  near  the  upper  edge,  and  at  the  bending  or 
angle  of  the  jaw.  It  takes  its  course  along  the  interior 
of  tlie  bone  (the  canal),  close  to  the  roots  of  the  teeth, 
and  sends  out  filaments  to  each  of  them.  Emerging 
through  the  lower  maxillary  foramen,  it  divides  into 
two  branches,  one  of  which  is  distributed  in  numerous 
ramifications  on  the  outside  of  the  lower  lip,  and  the 
other  in  fewer  ramifications  on  the  inside.  Tliese  are 
evidently  sensitive  fibrils,  the  power  of  motion  being 
derived  from,  the  seventh  pair  of  nerves. 

*'  The  fourth  branch  in  point  of  order,  but  which 
does  not  enter  the  '  dental  canal,'  is  the  gustatory  or 
Ungual  nerve,  the  largest  of  the  four.  It  is  singularly 
flat,  like  a  little  ribbon.  It  runs  along  the  inside  of 
the  lower  jaw,  and  a  branch  of  it  enters  a  foramen  in 
the  jaw  to  supply  the  roots  of  the  incisor  teeth ;  but 
the  main  nerve,  proceeding  obliquely  downward,  gives 
fibrils  to  the  submaxillary  glands,  and  to  the  glands 
and  muscles  at  the  base  of  the  mouth  generally.  These 
fibrils  form  true  plexuses  about  the  salivary  glands  and 
the  muscles  of  the  tongue.  They  anastomose  freely 
with  the  twelfth  pair  (the  linguales  or  motor  nerve  of 
the  tongue),  as  the  twelfth  had  already  done  with  the 
seventh  (the  'portio  dura').  The  gustatory  branch 
penetrates  the  substance  of  the  tongue  between  the 
stylo  and  genio-glossal  muscles,  passing  obliquely  to 


RICH   PLEXUSES  AND  LOOPED  FILAMENTS.        225 

the  surface  of  the  tongue,  and  terminating  in  the  pa- 
pillae. The  papillae,  thus  endowed  with  nervous  influ- 
ence, are  the  seat  of  the  sense  of  taste," 

Of  the  fifth  nerve  (in  man  and  in  the  horse)  Prof. 
Owen  (quoting  partly  from  Dr.  Swan),  says  ("Odon- 
tography," vol.  i,  pp.  Ixv-vi) : 

"  Ulie  nerves  of  the  teeth  are  derived  from  the  tri- 
geminal, or  fifth  pair,  of  which  the  second  division  sup- 
plies those  of  the  upper  ja^v,  the  third  division  those 
of  the  lower.     In  the  human  subject,  the  three  deutal 
branches  of  the  infra-orbital  nerve  intercommunicate 
by  their  primary  branches,  from  which,  and  from  a 
rich  plexus  formed  by  secondary  branches  upon  the 
membniue  lining  the  antrum,  two  sets  of  nerves  are 
sent  off  to  the  alveolar  processes  of  the  upper  jaw;  one 
set  (rami  dentales)  supplies  tlie  teeth,  the  other  [rami 
gingivales)  the  osseous  tissue  of  the  gums.     The  latter 
agree  in  number  with  the  intervals  of  the  teeth,  as  the 
proper  dental  nerves  do  with  the  teeth  themselves. 
These  two  sets  are  not,  however,  so  distinct  but  that 
some  intercommunications  are  established  between  the 
fine  branches  sent  off  in  their  progress  to  the  parts 
they  are  specially  destined  to  supply.     The  rami  den- 
tales take  the  more  direct  course  (through  the  middle 
part  of  tlie  osseous  tissue  to  the  teeth)  penetrate  the 
orifices  of  the  fangs,  and  form  a  rich  plexus  with 
rhomboidal  meshes  upon  the  coronal  surface  of  the 
pulp,  the  peripheral  elementary  filaments  returning 
into  the  plexus  by  loops.     In  the  lower  jaw  the  dental 
nerve,  besides  supplying  the  proper  nerves  to  the  teeth, 
also  forms  a  rich  plexus,  in  which  it  is  joined  by  some 
branches  from  the  division  of  the  nerve  that  afterward 
escapes  by  the  foramen  mentale,  and  from  this  plexus 


226  .        THE  FIFTH  PAIR  OF  NERVES. 

the  cancellous  tissue  of  the  bone  and  the  vascular 
gums  are  su23plied.  ♦  *  ♦  * 

"  In  the  horse  the  maxillary  plexus  is  most  devel- 
oped above  and  between  the  alveoli  of  the  three  pre- 
molar teeth.  It  is  less  complex  where  it  supplies  the 
molar  teeth,  their  alveoli,  and  the  gums.  In  the 
lower  jaw  of  the  horse  a  very  rich  plexus  begins  to  be 
formed  in  the  cancellous  substance  of  the  bone  by 
branches  of  the  dental  nerve,  soon  after  its  entry  into 
the  canal." 


VOCABULARY. 


Note. — The  definitions,  wliere  not  otherwise  credited,  are 
from  ''Diiuglison's  Medical  Dictionary." 

A. 

Ala  (plural,  alae).  Projections  from  the  median  line ;  as  the 
alee  nasi,  alae  of  the  uterus,  &c. 

Albumen.  An  important  organic  compound.  The  character- 
istic ingredient  in  the  white  of  egg  ;  abounds  in  the  serum 
of  the  blood,  in  chyle,  lymph,  skin,  muscles,  brain,  and  the 
juice  of  flesli ;  in  small  quantity  in  most  vegetable  juices, 
and  in  Bright's  disease  in  considerable  quantity  in  the  urine. 
It  is  the  foundation,  says  Liebig,  of  the  whole  series  of  pecu- 
liar tissues  which  constitute  those  organs  which  are  the 
seat  of  all  vital  actions.  C.  F.  Chandler. 

Alve'olar  Arches  are  formed  by  the  margins  or  borders  of 
the  two  jaws,  which  are  hollowed  by  the  alveoli. 

Alveolar  Arteky,  arises  from  the  internal  maxillary,  de- 
scends behind  the  tuberosity  of  the  upper  jaw,  and  gives 
branches  to  the  upper  molar  teeth,  gums,  periosteum,  mem- 
brane of  the  maxillary  sinus,  and  buccinator  muscle. 

Alveolar  Border.  The  part  of  the  jaws  that  is  hollowed  by 
the  alveoli. 

Alveolar  Membranes  are  very  fine  membranes,  situated  be- 
tween the  teeth  and  alveoli,  and  formed  by  a  portion  of  the 
sac  wliich  incloses  the  tooth  before  it  pierces  the  gum.  By 
some  this  membrane  has  been  called  the  '  alveolo -dental 
periosteum.' 

Alveolar  Vein.    This  has  a  distribution  similar  to  the  artery. 


228  VOCABULARY. 

AlviJ'olus  (pi.  alveoli).  The  alveoli  are  tlie  sockets  of  tlie 
teetli,  into  wliicL  they  are,  as  it  were,  driven.  Their  size 
and  sha]»  are  determined  by  the  teeth  which  they  receive, 
and  they  are  pierced  at  the  apex  by  small  holes  which  give 
passage  to  the  dental  vessels  and  nerves. 

Anastomo'sis  (*  a  mouth ').  Communication  between  two  ves- 
sels. By  considering  the  nerves  to  be  channels,  in  which  a 
nervous  fluid  circulates,  their  communication  likewise  has 
been  called  anastomosis.  By  means  of  anastomoses,  if  the 
course  of  a  fluid  be  arrested  in  one  vessel,  it  can  proceed 
along  others. 

Anisodac'tyle.  Hoofed  quadrupeds  with  toes  (on  the  hind- 
feet  at  least)  in  uneven  numbers,  as  one,  three,  or  five,  the 
latter  being  manifested  by  the  Proboscidians.  All  these  have 
a  simple  stomach  and  an  enormous  caecum.  Examples : 
Horse,  tapir,  rhinoceros,  elephant.  R.  Owen. 

Ante'eior  {ante  '  before ').  Great  confusion  has  prevailed  with 
anatomists  in  the  use  of  the  terms  before,  behind,  &c. 

(A  practical  definition  of  anterior  appears  to  be  (1)  parts 
in  front,  supposing  the  body  to  be  equally  divided  longi- 
tudinally from  right  to  left ;  (2)  parts  nearest  the  operator, 
parts  beyond  being  posterior) 

Antrum.  A  cavern.  A  name  given  to  certain  cavities  in 
bones,  the  entrance  to  which  is  smaller  than  the  bottom. 

Antrum  of  Highmore.  A  deep  cavity  in  the  substance  of  the 
superior  maxillary  bone,  communicating  with  the  middle 
meatus  of  the  nose.  It  is  lined  by  a  prolongation  of  the 
Schueiderian  membrane. 

Arach'koid  Me^ebrane.  a  name  given  to  several  mem- 
branes, which,  by  their  extreme  thinness,  resemble  spider- 
webs.  The  modems  use  it  for  one  of  the  membranes  of  the 
brain,  situate  between  the  dura  mater  and  pia  matelr.  It  is  a 
serous  membrane,  composed  of  two  layers,  the  external  being 
confounded,  in  the  greater  part  of  its  extent,  with  the  dura 
mater,  and,  like  it,  lining  the  interior  of  the  cranium  and  spi- 
nal canal ;  the  other  is  extended  over  the  brain,  from  which 
it  is  separated  by  the  pia  mater,  without  passing  into  the 
sinuosities  between  the  convolutions,  and  y^enetrating  into 
the  interior  of  the  brain  by  an  opening  at  its  posterior  part, 
under  the  '  corpus  callosum.'    It  forms  a  part  of  the  investing 


AN    AR3IET)    QVADirJPED.  229 

sheath  of  nerves,  as  they  pass  from  the  encephalic  cavities. 
Its  chief  uses  seem  to  be  to  envelop  and,  in  some  measure, 
protect  the  brain,  and  to  secrete  a  liuid  for  the  purpose  of 
keeping  it  in  a  state  best  adapted  for  the  performance  of  its 
functions. 

Are'ola.  a  diminutive  of  'area.'  Auatomists  understand  by 
areolae  the  interstices  between  the  fibers  composing  organs, 
or  those  existing  between  laminae,  or  between  vessels  which 
interlace  with  each  other. 

Abgen'ti  Nitras.  Nitrate  of  silver  ;  fuuar  caustic.  The  vir- 
tues of  nitrate  of  silver  are  tonic  and  escharotic.  It  is  given 
in  chorea,  epilepsy,  &c.;  locally,  it  is  used  in  various  cases  as 
an  escharotic.  Dose,  gr.  1-8  to  gr.  1-4,  in  pill,  three  times 
a  day. 

Armadil'lo.  (So  called  from  being  protected  or  armed  by  a 
scaly  covering  like  the  plate  armor  of  the  middle  ages.)  A 
genus  of  South  American  quadrupeds,  belonging  to  the  order 
of  edentata,  and  characterized  by  a  defensive  armor  of  small 
bony  plates,  covering  the  head  and  trunk,  and  sometimes  the 
tail.  Br  <t  tide. 

Articula'tiox.  The  union  of  bones  with  each  other,  as  well 
as  the  kind  of  union.  Articulations  are  generally  divided 
into  two  kinds — movable  and  immovable.  The  articulations 
are  subject  to  a  number  of  diseases,  which  are  generally  some- 
what severe;  they  may  be  physical,  as  wounds,  sprains,  lux- 
ations, &c.,  or  they  may  be  organic,  as  ankylosis,  extraneous 
bodies,  caries,  rheumatism,  gout,  &c. 

At'rophy.  Progressive  and  morbid  diminution  in  the  bulk  of 
the  whole  body  or  of  a  part.  Atrophy  is  generally  symi> 
tomatic.  Any  tissue  or  organ  thus  affected  is  said  to  be 
'  atrophied.' 

AuRic'iiLAR.  (The  ear.)  That  which  belongs  to  the  ear,  espe- 
cially the  external  ear. 

B. 

Batra'chia.     An  order  of  reptiles  including  toads,  frogs,  and 

salamanders.  Brande. 

One  of  the  five  great  classes  into  which  vertebrate  animals 

are  usually  divided,  though  some  writers  have  reduced  the 

class  to  the  rank  of  an  order  of  reptiles,  a  class  with  which 


230  VOCAB.ULARY. 

they  are  popularly  confounded.  The  batrachians  are  cold- 
blooded and  oviparous,  and  in  most  living  species  are  with- 
out scales,  and  the  blood  is  partly  aerated  through  the  skin. 
The  young,  for  the  most  part,  breathe  by  gills  like  those  of 
fishes;  they  assume  a  fish-like  form  (as  the  tadpole),  and 
finally,  when  adult,  with  few  exceptions,  lose  their  gills  and 
breathe  by  lungs,  like  true  or  scaly  reptiles.  They  generally 
have  limbs,  but  not  always.  Johnson's  N.  U.  Cyc. 

Bi'furcation.  (A  fork.)  Division  of  a  trunk  into  two 
branches,  as  the  biAircation  of  the  trachea,  aorta,  &c. 

Buccal.  That  which  concerns  the  mouth,  and  especially  the 
cheek. 

C. 

C^CUM.  The  blind  gnt ;  so  called  from  its  being  perforated  at 
one  end  only.  That  portion  of  the  intestinal  canal  which  is 
seated  between  the  termination  of  the  ileum  and  beginning 
of  the  colon,  and  which  fills,  almost  wholly,  the  right  iliac 
fossa,  where  the  peritoneum  retains  it  immovably.  Its  length 
is  about  three  or  four  fingers'  breadth.  The  ileo-caecal  valve, 
or  valve  of  Bauliin,  shuts  off  all  communication  between  it 
and  the  ileum,  and  the  *  Appendix  vermiformis  caeci'  is  at- 
tached to  it. 

In  the  horse  the  csecum  (^vater  stomach)  will  hold  four  gal- 
lons. A  horse  will  drink  at  one  time  a  great  deal  more  than 
his  stomach  will  contain  ;  but  even  if  he  drinks  a  less  quan- 
tity, it  remains,  not  in  the  stomach  or  small  intestines,  but 
passes  to  the  csecum,  and  is  there  retained,  as  in  a  reservoir, 
to  supply  the  wants  of  the  system.  TouatL 

Cal'culus.  a  diminutive  of  '  caix,'  a  lime-stone.  Calculi  are 
concretions,  which  may  form  in  every  part  of  the  animal 
body,  but  are  most  frequently  found  in  the  organs  that  act 
as  reservoirs,  and  in  the  excretory  canals.  They  are  met 
with  in  the  tonsils,  joints,  biliary  ducts,  digestive  passages, 
lachrymal  ducts,  mammse,  pancreas,  pineal  gland,  prostate, 
lungs,  salivary,  spermatic,  and  urinary  passages,  and  in  the 
uterus.  The  causes  which  give  rise  to  them  are  obscure. 
Those  that  occur  in  reservoirs  or  ducts  are  supposed  to  be 
owing  to  the  deposition  of  the  substances,  which  compose 
them,  from  the  fluid  as  it  passes  along  the  duct  ;  those  which 
occur  in  the  substance  oi  an  organ  are  regarded  as  the  pro- 


THE   USES   or   BONE  CELLS.  231, 

duct  of  some  clironic  irritation.    Their  gene.-al  effect  is  to 
irritate,  as  extraneous  bodies,  the  parts  with  wliich  they  are 
in  contact,  and  to  produce  retention  of  the  fluid  whence  they 
have  been  formed.     The  symptoms  difler,  according  to  the 
sensibility  of  the  organ  and  the  import-nnce  of  tlie  particular 
secretion  whose  discharge  they  impede.     Their  '  sol  ation '  is 
generally  impracticable.     Spontaneous  expulsion  or  extrac- 
tion is  the  only  way  of  getting  rid  of  them. 
CaNcel'LI.     •  Lattice- work.'    The  cellular  or  spongy  texture  of 
bone,  consisting  of  numerous  cells,  Communicating  with  each 
other.    They  contain  a  fatty  matter,  analogous  to  marrow, 
This  texture  is  met  with  principally  at  the  extremities  of 
long  bones,  and  some  of  the  short  bones  consist  almost  wholly 
of  it.     It  allows  of  the  expansion  of  the  extremities  of  bones, 
without  adding  to  their  weight,  and  deadens  concussions. 
Cannula.    Diminutive  of  canna,  '  a  reed.'    A  small  tube  of  gold, 
silver,  platinum,   iron,  lead,  wood,  elastic  gum,  or  gutta- 
percha, used  for  various  purposes  in  surgery. 
Cap'illahy  (from  capilkcs, '  a  hair  ')•     Hair  like ;  small. 
Capillary  Vessels  are  the  extreme  radicles  of  the  arteries 
and  veins,  which  togetiier  constitute  the  capillary,  interme- 
diate, or  peripheral  vascular  system— the  methse'mata  blood 
channels  of  Dr.  Marshall  Hall  (that  is,  the  system  of  vessels 
in  which  the  blood  undergoes  the  change  from  venous  to 
arterial,  and  conversely).     They  possess  an  action  distinct 
from  that  of  the  heart. 
Ca'ries.     (Rottenness.)     A  disease  of  bones  analogous  to  ulcer- 
ation  of  soft  tissues  ;  a  term  for  open  ulcer  of  bone  and 
chronic  ostitis  of  its  connective  tissue,  with  solution  of  the 
earthy  part.     It  begins  as  an  inflammation,  accompanied  by 
periostitis,  followed  by  exudation  'of  new  materials  and 
softening.     Sometimes  the  bone-cells  are  filled  with  a  red- 
dish fluid,  and  there  are  masses  of  tubercle.     After  caries 
has  existed  for  some  time  the  abscess  bursts  ;   aperture  re- 
mains open,  discharging  a  fluid  and  particles  of  bone  ;   a 
probe  is  felt  to  sink  into  a  soft,  gritty  substance-Carious 
bone      Caries  is  molecular  death  of  bone ;  necrosis  is  death 
of  a  mass  of  bone.  WUlard  Parker 

Cakot'ids.     The  great  arteries  of  the  neck,  which  carry  blood 
to  the  head. 


232  V0C4BULART. 

Car'tilage.  a  solid  part  of  the  animal  body,  of  a  consistence 
between  bone  and  ligament,  which  in  the  fetus  is  a  substi- 
tute for  bone,  bi?t  in  the  adult  exists  ouij  in  the  joints,  at 
the  extremities  of  the  ribs,  &c. 

Cervical.  Everything  which  concerns  the  neck,  especially 
the  back  part. 

Chevrotain',  a  species  of  the  genus  Moschus,  related  to  the 
dser,  but  having  no  horns,  and  otherwise  peculiar.  It  is 
small,  light,  and  graceful,  and  lives  in  the  mountains  of  Asia, 
from  the  Altai  to  Java.  Dana. 

Choroid  Membrane.  A  thin  membrane,  of  a  very  dark  color, 
which  lines  the  sclerotic  internally.  It  is  situate  between  the 
sclerotic  and  retina,  has  an  opening  posteriorly  for  the  pas- 
sage of  the  optic  nerve,  and  terminates  anteriorly  at  the  great 
circumference  of  the  iris,  where  it  is  continuous  with  the  cili- 
ary processes.  The  internal  surface  is  covered  with  a  dark 
pigment,  consisting  of  several  layers  of  pigment  cells.  Its 
use  seems  to  be  to  absorb  the  rays  of  light  after  they  have 
traversed  the  retina. 

Cil'iaky.  Relating  to  the  eyelashes,  or  to  cilia.  This  epithet 
has  also  been  applied  to  different  parts,  which  enter  into  the 
structure  of  the  eye,  from  the  resemblance  between  some  of 
them  (the  ciliary  processes)  and  the  eyelashes. 

Colon.  That  portion  of  the  large  intestines  which  extends 
from  the  caecum  to  the  rectum.  The  colon  is  usually  divided 
into  four  portions.  1.  The  right  lumbar  or  ascending  colon, 
situate  in  the  right  lumbar  region,  and  beginning  at  the 
csscum.  2.  The  transverse  colon — transverse  arch  of  the 
colon — the  portion  which  crosses  from  the  right  to  the  left 
side,  at  the  upper  part  of  the  abdomen.  3.  The  left  lumbar 
or  descending  colon,  extending  from  the  left  part  of  the  trans- 
verse arch,  opposite  the  outer  portion  of  the  leftkidney,  to 
the  corresponding  iliac  fossa.  4.  The  iliac  colon,  or  sigmoid 
flexure  of  the  colon  ;  the  portion  which  makes  a  double  cur- 
vature in  the  left  iliac  fossa,  and  ends  in  the  rectum. 

In  the  horse  the  c:jlon  is  exceedingly  large,  and  is  capable 
of  containing  no  less  than  twelve  gallons  of  liquid  or  pulpy 
food.  It  is  of  considerable  length  ;  completely  traversing  the 
diameter  of  the  abdominal  cavity,  it  is  then  reflected  upon 
itself,  and  retraverscs  the  same  space.  Touatt. 


THE   USES   OF   COMPARATIVE   ANATOMY.  233 

Com'missures.  The  point  of  union  between  two  parts;  thus 
the  commissures  of  the  eyelids,  lips,  &c.,  are  the  angles  which 
they  form  at  the  place  of  union. 

Comparative  Anat'omy.  The  science  which  treats  of  the 
structure  and  relation  of  organs  in  the  various  branches  of 
the  animal  kingdom^  without  a  knowledge  of  which  it  is  hn- 
possible  to  understiind  the  beautifully  progressive  develop- 
ment of  organization,  necessary  even  for  the  full  comprehen- 
sion of  the  uses  of  many  parts  of  the  human  body,  which, 
apparently  rudimentary  and  useless  in  man,  are  highly  de- 
veloped in  other  animals.  This  science  is  also  the  basis  of 
physiology  and  the  natural  classification  of  animals. 

Amsrkan  Oyelopedia. 

Con'dyle.  An  articular  eminence,  round  in  one  direction,  flat 
in  the  other.  A  kind  of  process,  met  with  more  particularly 
in  the  ginglymoid  joints,  snch  as  the  condyles  of  tlie  occipi- 
tal, inferior  maxillary  bone,  &c. 

Congen'ital  (from  con  and  genitics,  'begotten').  Diseases 
which  infants  have  at  birth  ;  hence,  congenital  affections  are 
those  that  depend  on  faulty  conformation,  as  congenital  her- 
nia, congenital  cataract,  &c. 

CoNJUNCTi'vA  Membra' NA.  A  mucous  membrane,  so  called 
because  it  unites  the  globe  of  the  eye  with  the  eyelids.  It 
covers  the  anterior  surface  of  the  eye,  the  inner  surface  of  the 
eyelids,  and  the  '  caruncula  lachrymalis.'  It  possesses  great 
general  sensibility,  communicated  to  it  by  the  fifth  pair  of 
nerves. 

Copyba'ra  is  the  largest  known  quadruped  of  the  order  Ro- 
dentia,  and  belongs  to  the  family  Cavidse.  It  is  an  aquatic 
animal,  a  native  of  Soath  America,  and  feeds  on  vegetable 
food  exclusively.  Its  dentition  resembles  that  of  the  cavy, 
except  that  the  grinding  teeth  are  formed  of  many  trans- 
verse plates,  the  number  of  plates  increasing  as  the  animal 
advances  in  age.  It  is  inoffensive  and  easily  tamed.  The 
flesh  is  esteemed  good  food.  It  is  somewhat  smaller  than 
the  common  hog.  Johnson's  New  UnideTsal  Gydapedia. 

COR^PUSCTLE.  One  of  the  ultimate  morphological  elements  of  the 
body.  They  exist  at  some  time  or  other  in  all  the  tissues  of 
the  body,  governing  their  vital  actions.  The  white  and  red 
corpuscles  of  the  blood,  epithelial  bodies  and  ganglionic  nerve 


234  VOCABULARY. 

cells  are  examples.  They  are  mainly  compossd  of  protoplasm 
and  contain  in  their  interior  bodies  called  nuclei,  in  wbich 
are  still  smaller  ones  called  nucleoli.        T.  E.  Satterthwaite. 

Correla'tion  (mutual  relation)  of  Forces  (otherwise  called 
'Transmutation  of  Force  or  Energy').  A  phrase  of  recent 
origin,  employed  to  express  the  theory  that  any  one  of  the 
various  forms  of  physical  force  may  be  converted  into  one  or 
more  of  the  other  forms.  The  cardinal  point  in  this  theory 
is  the  doctrine  of  heat  and  its  relation  to  other  agents,  espe- 
cially to  mechanical  motion.  For  example,  the  heat  mani- 
fested when  we  rub  two  flat  surfaces  briskly  against  each 
other,  is  only  our  own  muscular  motion  checked  by  the  fric- 
tion, and  changed  thereby  into  the  heat  wdiich  the  surfaces 
reveal.  On  the  other  hand,  this  muscular  motion  is  only  the 
beat  of  our  bodily  frame  expending  itself  in  this  way.  In 
either  case  the  energy  has  not  been  annihilated,  but  only 
transferred,  and  appears  in  a  new  form. 

Johnson's  N.  U.  Cyc,  article  revised  by  J.  H.  Seelye. 

Crura.  The  plural  of  cms, '  a  leg.'  Applied  to  some  parts  of 
the  body,  from  their  resemblance  to  legs  or  roots,  as  the 
'  crura  cerebri,'  '  crura  cerebelli,'  &c. 

Cul-de-sac.  Any  bag-shaped  cavity,  tubular  vessel,  or  organ, 
open  only  at  one  end.  Dana. 

D. 

Dental  Canal.    The  bony  canals  through  which  the  vessels 

and  nerves  pass  to  the  interior  of  the  teeth. 
Dental  Cavity.     A  cavity  in  the  interior  of  the  teeth,  in  which 

is  situate  the  dental  pulp.    (More  properly  the  pulpal  cavity.) 
Dental  Pulp.      The  pultaceous  substance,  of  a  reddish-gray 

color,  very  soft  and   sensible,  which  fills  the  cavity  of  the 

teeth.     It  is  well  supplied  with  capillary  vessels. 
Dentig'erous.       Tooth-carrying,   as   dentigerous  cysts ;     one 

containing  teeth. 
Dermal.     Relating  or  belonging  to  the  skin. 
Dermatoid  or  Dermoid.     Tliat  which  is  similar  to  the  skin. 

This  name  is  given  to  diflerent  tissues  which  resemble  the 

skin.     The  dura  mater  has  been  so  called  by  some. 
Deter'gents.     Medicines  wdiich  possess  the  power  to  deterge 

or  cleanse  parts,  as  wounds,  ulcers,  &c. 


THE   USE   OF  A   DIVERTICULUM.  2oO 

Diabe'tes.  a  disease  characterized  by  great  augmentation  and 
often  mauifesi  alteration  in  the  secretion  of  urine,  with  ex- 
cessive thirst  and  progressive  emaciation.  The  quantity  of 
urine  discharged  in  24  hours  is  sometimes  30  pints  and  up- 
ward, each  pint  containinp^  2|  ounces  saccharine  matter. 

Di'aphhagm.  1.  A  dividinof  membrane  or  thin  partition,  com- 
monly with  an  opening  through  it.  2.  The  muscle  separa- 
ting- the  chest  or  thorax  from  the  abdomen  or  lower  bellv  ; 
the  midriff.  Webster. 

Diath'esis.  Disposition,  constitution,  affection  of  the  body; 
predisposition  to  certain  diseases  rather  than  to  others.  The 
principal  diatheses  are  the  cancerous,  scrofulous,  scorbutic 
(pertaining  to  scurvy),  rheumatic,  gouty,  and  calculous. 

DiVERTic'uLUM.  A  blind  tube  branching  out  from  the  course 
of  a  larger  one.  An  organ  which  is  capable  of  receiving  an 
unusual  quantity  of  blood,  when  the  circulation  is  obstructed 
or  modified  elsewhere,  is  said  to  act  as  a  diverticulum. 

In  the  marsupials  only  four  teeth  (one  in  each  jaw  on  each 
side)  are  deciduous.  The  permanent  set  are  developed  from 
duerticula  of  the  sacs  which  originated  the  first  set.       Gill. 

Dugong'.  a  herbivorous,  cetaceous  animal  with  a  tapering  body 
ending  in  a  crescent-shaped  fin.  Tbe  fabled  mermaid  seems 
to  have  been  founded  on  the  dugong,  Gilhert.     Brande. 

It  is  generally  from  8  to  12  feet  long,  though  it  is  said  to 
sometimes  attain  the  length  of  25  feet.  The  ufjper  lip  is 
thick  and  fleshy  and  forms  a  kind  of  snout ;  the  upper  jaw 
bends  downward  almost  to  a  right  angle  ;  eyes  small,  with  a 
nictitating  membrane ;  the  skin  is  thick  and  smooth.  Its 
flesh  is  said  to  resemble  beef,  and  is  prized  as  food.  The  oil 
is  recommended  as  a  substitute  for  cod -liver  oil.        J.'s  Gyc. 

Dura  Mater.  (Hard.)  The  outermost  of  three  membranes 
enveloping  the  brain  and  spinal  cord.  Within  the  skull 
it  so  completely  joins  the  bones  that  it  may  be  regarded 
as  their  endosteum.  Within  the  spinal  canal  it  becomes 
a  fibrous  tube,  separated  from  the  vertebrae  (which  have 
no  endosteum)  by  a  loose,  areolar,  fatty  tissue  and  a  plexus 
of  veins.  It  sends  out  sheaths  for  the  nerves  as  they  go 
through  their  foramina.  It  is  usually  studded,  except  in 
infancy,  by  minute  whitish  masses  (Paccionian  bodies)  whose 
use  is  not  known.    Its  inner  surface  is  covered  with  pave- 


236  VOCABULARY. 

ment  epithelium,  and  perhaps  by  the  parietal  layer  of  the 
arachnoid  membrane.  1  b  V'. 

E. 

Econ'omy.  By  the  term 'animal  economy'  is  understood  the 
aggregate  of  the  laws  which  govern  the  organism.  The  word 
economy  is  also  used  for  the  aggregate  of  parts  which  con- 
stitute man  or  animals. 

Edenta'ta.  In  natural  history,  an  order  of  animals  that  are 
destitute  of  front  teeth,  as  the  ariuadiilo  and  ant-eater.    Bdl. 

Edsn'tulus.     One  without  teeth. 

Em'bryo.  The  fecundated  garni,  in  the  early  stages  of  its  de- 
velopment in  utsro.  At  a  certain  period  of  its  increase,  the 
nama  '  fetus'  is  given  to  it,  but  at  what  period  is  not  deter- 
mined. Generally,  the  embryo  state  is  considered  to  extend 
to  the  period  of  quickening. 

Encsphali'tis.  This  term  has  been  used  by  some  nosologists 
(classifiers  of  diseases)  synonymously  with  '  cephalitis '  and 
'phranitis.'  By  others  it  has  been  appropriated  to  inflam- 
mation of  the  brain,  in  contradistinction  to  that  of  the  mem- 
branes. 

E'ocene.  In  geology,  a  term  applied  to  the  earlier  tertiary  de- 
posits, in  which  are  a  few  organic  remains  of  existing  species 
of  animals.  Hence  the  term  eocene  (recent),  which  denotes 
the  dawn  of  the  existing  state  of  things. 

Dana.  Lijell.  Mantell. 
In  America  the  eacene  strata  contain  numerous  fossils, 
mostly  marine  moUusks,  but  also  include  some  gigantic  ver- 
tebrates, a  carnivorous  cetacean  seventy  feet  in  length,  and  a 
shark  of  which  the  teeth  are  sometimes  six  inches  in  length. 
The  Wyoming  beds  have  furnished  the  remains  of  a  remark- 
able  group  of  mammals,  which  are  thought  by  Prof.  Marsh' 
to  form  a  new  order,  and  which  he  has  named  '  Dinocerata.* 
The  largest  of  these  (Dinoceras  mirabilis)  had  the  bulk  of  an 
elephant,  and  was  provided  with  three  pairs  of  horns  and  a 
pair  of  great  saber-like  canine  teeth.      Johnson's  JSf.  XT.  Gye. 

Epider'mis.  a  modification  of  the  epithelium,  molded  to  the 
papillary  layer  of  the  true  skin  ;  composed  of  agglutinated, 
flattened  cells,  whic^x  are  developed  in  the  liquor  sanguinis, 
the  latter  being  poured  out  on  the  true  skin's  external  sur- 
face.   In  the  deeper  layers  the  cells  are  rounded  or  columnar, 


THE   U^^IYERSE   A   SERIES   OF   CHAN-GES.         237 

containing  in  most  races  of  men  more  or  less  pigmentary 
matter,  which  gives  the  skin  its  various  shades  from  black 
to  white.  It  is  penetrated  b)^  the  ducts  of  the  skin's  sweat- 
glands  and  oil-glands  ;  becomes  hard  in  palms  of  hands; 
otherwise  is  soft.  The  hair  and  nails  are  modifications  of  it. 
On  leaves  it  is  penetrated  by  the  stomata,  transmitting 
exhalations  and  absorbing  carbonic  acid,  the  most  important 
part  of  plant  food.  /^^-^^ 

Epithe'lium.  (Soft,  delicate,  tender.)  The  layer  of  cells  lin- 
ing serous  (closed)  and  mucous  (open)  cavities,  the  mucous 
epithelium  being  continuous  with  the  epidermis.  (Mucous 
is  formed  by  the  bursting  of  epithelial  cells.)  Illd. 

Esoph'agus.     The  gullet.     Extends  from  pharynx  to  stomach. 
Ethmoid.     Sieve-like.     The  ethmoid  lone  is  one  of  the  eight 
bones  which  compose  the  cranium,  so  called  because  its  up- 
per plate  is  pierced  by  numerous  holes.     It  is  situate  at  the 
anterior,  inferior,  and  middle  part  of  the  cranium. 
Evolu'tion.     According  to  the  hypothesis  of  evolution,  in  its 
simplest  form,  the  universe  as  it  now  exists  is  the  result  5f 
"an  immense  series  of  changes,"  related  to  and  dependent 
upon  each  other,  as  successive  steps,  or  rather  growths,  con- 
stituting a  progress';  analogous  to  the  unfolding  or  evolving 
of  the  parts  of  a  living  organism.     Evolution  is  defined  by 
Herbert  Spencer  as  consisting  in  a  progress  from  the  homo- 
geneous to  the  heterogeneous,  from  general  to  special,  from 
the  simple  to  the  complex ;  and  this  process  is  considered  to 
be  traceable  in  the  formation  of  the  worlds  in  space,  in  the 
multiplication  of  the  types  and  species  of  plants  and  animals 
on  the  globe,  in  the  origination  and  diversity  of  languages, 
literature,  arts,  and  sciences,  and  in  all  the  changes  of  human 
institutions  and  society.  Henry  Hartshorne. 

The  animal  kincrdom  displays  a  unity  of  plan  or  a  correla- 
tion of  parts  by  which  common  principles  are  traced  through 
the  most  disguising  diversities  of  form,  so  that  in  aspect,  struc- 
ture, and  functions  the  various  tribes  of  animals  pnss  into 
each  other  by  sliirht  and  gradual  transitions.  The  arm  of  a 
man,  the  fore  limb  of  a  qnndrunod,  the  wing  of  a  bird,  and 
the  fin  of  a  fish  are  homologous,  thnt  is,  they  contain  the 
same  essential  parts,  modified  in  correspondence  with  the  dif- 
ferent circumstances  of  the  animal ;   and  so  with  the  other 


238  VOCABULAllY. 

organs.  Prof.  Cope  says :  "  Every  individual  of  every  species 
of  a  given  brancli  of  the  animal  kingdom  is  composed  of  ele- 
ments common  to  all,  and  the  diiForcaces  wliicii  are  so  radi- 
cal in  the  higher  grades  are  but  the  modifications  of  the  same 
elemental  parts."  E.  L.  Toumans. 

Exfolia'tiqn  (from  ex  andi  folium,  '  a  leaf).  By  this  is  meant 
the  separation  of  the  dead  portions  of  a  bone,  tendon,  apon- 
eurosis (a  white  shining  membrane),  or  cartilage,  under  the 
form  of  lamelke  (small  scales).  Exfoliation  is  accomplished 
by  the  instinctive  action  of  the  parts,  and  its  object  is  to  de- 
tach the  dead  portions  from  those  subjacent,  which  are  still 
alive.  For  this  purpose  the  latter  throw  out  fleshy  granula- 
tions, and  a  more  or  less  abundant  suppuration  occurs,  which 
tends  to  separate  the  exfoliated  part — now  become  an  extra- 
neous body. 

Exosro'sis.  An  osseous  tumor,  which  forms  at  the  surface  of 
bones,  or  in  their  cavities. 

ExosTOiis  Dentium.     Exostosis  of  the  teeth. 

F. 

Ferru'ginous  (chalyb'eate).  Of  or  belonging  to  iron ;  contain- 
ing iron.  Any  medicine  into  which  iron  enters,  as  chalyb- 
eate mixture,  pills,  waters,  &c. 

Fe'tus.     See  '  embryo.' 

Fiber.  An  organic  filament,  of  a  solid  consistence,  and  more  or 
less  extensible,  which  enters  into  the  composition  of  every 
animal  and  vegetable  texture, 

Fil/'ament.  a  thread.  This  word  is  used  synonymously  with 
fibril ;  thus  we  say  a  nervous  or  cellular  filament  or  fibril. 

Fis'tula.  '  A  pipe  or  reed.'  A  solution  of  continuity  (a  division 
of  parts  previously  continuous)  of  greater  or  less  depth  and 
sinuosity,  the  opening  of  which  is  narrow,  and  the  disease 
kept  up  by  an  altered  texture  of  parts,  so  that  it  is  not  dis- 
posed to  hoal.  A  fistula  is  '  incomplete  '  -or  '  blind'  when  it 
has  but  one  opening,  and  '  complete '  when  there  are  two,  the 
one  communicating  Avith  an  internal  cavity,  the  other  exter- 
nally. It  is  lined  in  its  whole  course  by  a  membrane  which 
seems  analogous  to  mucous  membranes. 

Fol'ltcle.  a  follicle  or  cryi)t  is  a  small,  roundish,  hollow 
bodv,  situate  in  the  substance  of  the  skia  or  mucous  mem- 
branes, and  constantly  pouring  the  fluid  which  it  secretes  on 


USES  OF  GASTRIC  JUICE.  239 

their  surfaces.  The  use  of  the  secretion  is  to  keep  the  parts 
on  which  it  is  poured  supple  and  moist,  and  to  preserve  them 
from  the  action  of  irritating  bodies  with  vvliich  they  have  to 
come  in  contact. 

Foua'men.  Any  cavity  pierced  through  and  thi-ough.  Also 
the  orifice  to  a  canal. 

Fossa.  A  cavity  of  greater  or  less  depth,  the  entrance  to  which 
is  always  larger  than  the  base. 

FniENUitf.  A  small  bridle.  A  name  ^ven  to  several  membran- 
ous folds,  which  bridle  and  retain  certain  organs. 

Frontal.  Bone.  A  double  bone  in  the  fetus,  single  in  the  adult, 
situate  at  the  base  of  the  cranium,  and  at  the  superior  part 
of  the  face. 

Function.  The  action  of  an  organ  or  system  of  organs.  Any 
act  necessary  for  accomplishing  a  vital  phenomenon.  A 
function  is  a  special  oflBce  in  the  animal  economy,  whicli  has 
as  its  instrument  an  organ  or  apparatus  of  organs. 

Fungus.  The  mushroom  order  of  plants.  In  pathology  the 
word  is  commonly  used  synonymously  with  fungosity  (my- 
cosis). 

Fungus  H^mato'des  (Hoematodes  Fungus),  An  exceedingly 
alarming  carcinomatous  (cancerous)  affection,  which  was  first 
described  with  accuracy  by  Mr.  Jolm  Bums,  of  Glasgow.  It 
consists  in  the  development  of  cancerous  tumors,  in  which 
the  inflammation  is  accompanied  with  violent  heat  and  pain, 
and  with  fungus  and  bleeding  excrescences. 

G. 

Gang'lion.  Nervous  ganglions  are  enlargements  or  knots  in 
the  course  of  a  nerve. 

Gastric.     Belonging  or  relating  to  the  stomach. 

Gastric  Juice.  A  fluid  secreted  from  the  mucous  membrane 
of  the  stomach.     It  assists  digestion. 

Gentian  Wine  (vinum  gentiange  compositum,  or  wine  bitters). 
'Gentiana  Lutea'  is  the  systematic  name  of  the  officinal 
gentian.  The  plant  is  common  in  the  mountains  of  Europe. 
The  root  is  almost  inodorous,  extremely  bitter,  and  yields 
its  virtues  to  ether,  alcohol,  and  water.  It  is  tonic  and 
stomachic,  and,  in  large  doses,  aperient.  It  is  most  fre- 
quently, however,  used  in  infusion  or  tinctui-e. 


240  VOCABULARY. 

GEOL'oaY  is  tliat  brancTi  of  natural  science  whicli  treats  of  tlie 
structure  of  the  crust  of  the  earth  and  the  mode  of  formation 
of  its  rocks,  together  with  the  history  of  physical  changes 
and  of  life  on  our  planet  during  tlie  successive  stages  of  its 
history.  It  has  been  inferred  that  its  actual  crust  must  be 
very  thick,  perhai^s  not  less  than  2,500  miles.  Geology  de- 
pends upon  mineralogy  for  its  knowledge  of  tho  constituents 
of  rocks,  and  upon  chemistry  and  physics  for  its  knowledge 
of  the  laws  of  change ;  and  in  its  study  of  fossil  remains  it  is 
closely  connected  with  the  sciences  of  zoology  and  botany. 
A  knowledge  of  geology  lies  at  the  base  of  i^hysical  geogra- 
phy, and  is  essential  to  the  skillful  prosecution  of  mining 
and  other  useful  arts.  J.  W.  Dawson. 

The  facts  proved  by  geology  are  that  during  an  immense 
but  unknown  period  the  surface  of  the  earth  has  undergone 
successive  changes  ;  land  has  sunk  beneath  the  ocean,  while 
fresh  land  has  risen  up  from  it  ;  mountain  chains  have  been 
elevated  ;  islands  have  been  formed  into  continents,  and  con- 
tinents submerged  till  they  have  become  islands  ;  and  these 
changes  have  taken  place,  not  once  merely,  but  perhaps 
hundreds,  perhaps  thousands  of  times.  A,  L.  Wallace. 

Prof.  Dana  says  the  "  earth  was  first  a  featureless  globe  of 
fire  ;  then  had  its  oceans  and  dry  land  ;  in  course  of  time  re- 
ceived mountains  and  rivers,  and  finally  all  those  diversities 
of  surface  which  now  characterize  it." 

Gl^ind.  (An  acorn  ;  a  kernel.)  Softish,  granular,  lobated  or- 
gans, composed  of  vessels  and  a  particular  texture,  which 
draw  from  the  blood  the  luolecules  necessary  for  the  forma- 
tion of  new  fluids,  conveying  them  externally  by  means  of 
one  or  more  excretory  ducts.  Each  gland  has  an  organiza- 
tion peculiar  to  it,  but  we  know  not  the  intimate  nature  of 
the  glandular  texture, 

Guana'co.  The  *  Auchonia  Huan.ica,'  a  species  of  the  genus  of 
ruminant  mammals  to  which  the  llama  belongs.  It  inhabits 
the  Andes,  and  is  domesticated.     It  is  allied  to  the  camel. 

Webster, 

The   guanaco  is   especially  abundant   in  Patagonia  and 

Chili,  where  it  forms  larg^  flocks.     It  is  about  three  feet  high 

at  the  shoulders,  and  is  extremely  swift.     In  domestication  it 

is  ill-tempered,  and  has  a  disagreeable  habit  of  ejecting  saliva 


HISTOLOGY— IIUMAX,   CO^IPAKATIVE,    ETC.       241 

upon  unwelcome  visitors.     In  its  wild  state  it  seldom  drinks 
water.     lis  flesh  is  edible  and  its  skin  valuable. 

Johnson's  N.  TJ.  Cyc- 
H. 

Haversian  Canals.  (Canals  of  Havers,  nutritive  canals,  &c.) 
The  canals  through  which  the  vessels  pass  to  the  bones. 
They  are  lined  by  a  very  fine  lamina  of  compact  texture,  or 
are  formed  in  the  texture  itself.  There  is  generally  one  large 
nutritious  canal  ia  a  long  bone,  situate  toward  its  middle. 

Hia'tus.  a  foramen  or  aperture.  Mouth.  The  vulva.  Also 
yawning. 

Htstol'ogy  is  the  branch  of  anatomy  which  treats  of  the  minute 
structure  of  the  tissues  of  which  living  beings  are  composed. 
It  is  divided  into  '  human  histology,'  which  treats  of  the  tis- 
sues of  man  ;  '  comparative  histology,'  which  treats  of  the  tis- 
sues of  the  lower  animals,  and  '  vegetable  histology,'  which 
treats  of  the  tissues  of  plants.  Each  of  these  divisions  may 
be  subdivided  into  'normal'  and  'pathological'  histology, 
the  first  referring  to  the  healthy  tissues,  the  second  investi- 
gating the  changes  they  undergo  in  disease.    J.  J.  Woodward. 

Hoove.  A  disease  in  cattle,  consisting  in  the  excessive  inflation 
of  the  stomach  by  gas,  ordinarily  caused  by  eating  too  much 
green  food.  Gardner. 

Hyper' TROPHY.  The  state  of  a  part  in  which  the  nutrition  is 
performed  with  greater  activity,  and  which  on  that  account 
at  length  acquires  unusual  bulk.  The  part  thus  aflfected  is 
said  to  be  hypertrophied  or  hypertrophous. 

I. 

Infiltra'tion.  To  filter ;  effusion.  The  accumulation  of  a 
fluid  in  the  areolae  of  a  texture,  and  particularly  in  the  areo- 
lar membrane.  The  fluid  effused  is  ordinarily  the  '  liquor 
sanguinis,'  sound  or  altered  ;  sometimes  blood  or  pus,  faeces 
or  urine.  When  infiltration  of  a  serous  fluid  is  general,  it 
constitutes  'anasarca'  (dropsy) ;  when  local,  '  oedema.' 

Intersti^tial.  Applied  to  that  which  occurs  in  the  interstices 
of  an  organ,  as  interstitial  absorption,  interstitial  pregnancy, 
&c.     (See  '  Suppuration.') 

Intka-uterine.     (Tntr.7,  '^vith'm,'  uterus,  'the  womb.')     That 
which  takes  place  within  the  womb,  as  intra-uterine  life. 
11 


24:2  YOCABULART. 

Ikis.  So  called  from  its  resembling  the  rainbow  in  a  variety  of 
colors.  A  membrane,  stretched  vertically  at  the  anterior 
part  Of  the  eye,  in  the  midst  of  the  aqueous  humor,  in  which 
it  forms  a  kind  of  circular,  flat  partition,  separating  the  an- 
terior from  the  posterior  chamber.  It  is  perforated  by  a  cir- 
cular opening  called  the  pupil,  which  is  constantly  varying 
its  dimensions,  owing  to  the  contractions  of  the  fibers  of  the 
iris. 

Isodac'tyle.  Hoofed  quadrupeds  with  toes  in  even  number,  as 
two  or  four,  and  which  have  a  more  or  less  complicated 
stomach,  with  a  moderate-sized,  simple  caecum.  Examples: 
Ox,  hog,  peccary,  hippopotamus.  M.  Owen. 

L. 

Lach'rymal.  Belonging  to  the  tears.  This  epithet  is  given 
to  various  parts. 

Lacuna  of  Bone.  Certain  dark,  stellate  spots,  with  thread- 
like lines  raliating  from  them,  seen  under  a  high  magnifying 
power.  These  were  first  believed  to  be  solid  osseous  cor- 
puscles or  cells  (corpuscles  of  Purkinje),  but  are  now  re- 
garded as  excavations  in  the  bone,  with  minute  tubes  or 
canalic'uli  proceeding  from  them  and  communicating  with 
the  Haversian  canals.  The  lacunae  and  canaliculi  are  fibers 
concentrated  in  the  transit  of  nutrient  fluid  through  the  osse- 
ous tissue. 

Lam'ina.  a  thin,  flat  part  of  a  bone ;  a  plate  or  table,  as  the 
cribriform  lamina  or  plate  of  the  ethmoid  bone.  Lamina  and 
lamella  are  generally  used  synonymously,  although  the  latter 
is  properly  a  diminutive  of  the  former. 

Lesio  t.  Derangement,  disorder ;  any  morbid  change,  either  in 
the  exercise  of  functions  or  in  the  texture  of  organs.  '  Or- 
ganic legion '  is  synonymous  with  organic  disease. 

Lipo'ma.     a  fatty  tnmor  of  an  encysted  or  other  character. 

Lipo:m'atous.  Having  the  nature  of  lipoma,  as  a  lipomatous 
mass. 

Liquor  Sang'uinis.  A  term  given  by  Dr.  B.  Babington  to  one 
of  the  constituents  of  the  blood,  the  other  being  the  red  par- 
ticles. It  is  the  eflfused  material  (called  plasma,  coagulable 
or  plastic  lymph,  intercellular  fluid,  &c.),  from  which  the  cells 
obtain  the  constituents  of  the  different  tissues  and  secretions. 


M0LAE3   WITH   C02^'E-LIKE    PnOJECTIOXS.         243 


M. 

Malar.    Belonging  to  the  clieek,  as  the  malar  bone. 

Malar  Process.    Z/gomatic  process.    (Cheek  bone  process.) 

Masseter.  a  muscle  situate  at  the  posterior  part  of  the  cheek, 
and  lying  upon  the  ramus  of  the  lower  jawbone.  Its  office  is 
to  raise  the  lower  jaw  and  to  act  in  mastication. 

Mas'todon.  An  extinct  genus  of  quadrupeds.  When  alive  it 
must  have  been  twelve  or  thirteen  feet  high,  and,  including 
the  tusks,  about  twenty-five  feet  long.  The  tusks  measure 
ten  feet  eleven  inches,  about  two  and  a  Imlf  feet  being  im- 
planted in  the  socket.  According  to  Owen,  tlie  teeth  are 
seven  on  each  side,  above  and  below.  The  molars  have 
wedge-shaped,  transverse  ridges,  the  sumtnits  of  which  are 
divided  by  a  depression  lengthwiss  with  the  tooth,  and  sub- 
divided into  cones,  more  or  less  resembling  the  teats  of  a  cow. 
In  some  species  there  are  from  three  to  five  ridges  to  each 
posterior  molar;  in  other  species  five  or  more.  0.  C.  Marsh. 
(The  mastodon  takes  its  name  from  the  mastoid  or  nipple- 
like processes  of  its  teeth.) 

Mastoid.     Having  the  form  of  a  nipple. 

Max'illary.     Relating  or  belonging  to  the  jaws. 

Mea'tus.     a  passage  or  canal. 

Median  Line.  A  vertical  line,  supposed  to  divide  a  body  lon- 
gitudinally into  two  equal  parts,  the  one  right,  the  other  left. 

Med'ullary.    Relating  to  the  marrow,  or  analogous  to  marrow. 

Megathe'riu.m.  An  extinct  genus  of  Quaternary  mammals. 
'  Megatherium  Cuvieri,'  from  South  America,  exceeded  the 
rhinoceros  in  size,  its  skeleton  measuring  eighteen  feet  in 
"length.  The  vertebra  of  the  tail  are  very  large  and  power- 
ful,  and  that  organ,  with  the  hind-legs,  seems  to  have  formed 
a  support  for  the  heavy  body,  while  th'^  huge  fore-legs  were 
employed  in  breaking  the  branches  from  trees  ojj  tearing 
them  down  for  food.  There  are  four  toes  in  front  and  two 
behind.  The  teeth,  five  above  and  four  below  on  each  side, 
resemble  those  of  the  sloths.  They  grew  from  persistent 
pulps,  and  are  deeply  implanted  in  the  jaws  ;  they  have  a 
grinding  surface  of  triangular  ridges,  and  were  fitted  for  mas- 
ticating coarse  vegetable  food.  0.  C.  Marsh. 
Membrane.     A  name  given  to  different  thin  organs,  represent- 


244  VOCABULARY. 

ing  a  species  of  supple  and  more  or  less  elastic  webs,  varying 
in  their  structure  a'nd  vital  properties,  and  intended,  in  gen- 
eral, to  absorb  or  secrete  certain  fluids,  and  to  separate,  en- 
velop, and  form  other  organs.  Bichat  has  divided  the  mem- 
branes into  simple  and  compound. 

Membha'na  Nic'titans.  The  '  haw '  of  the  horse's  eye.  It  is 
a  triaugular-slmped  cartilage,  concealed  within  the  inner  cor- 
ner of  the  eye,  and  is  black  or  pied.  It,  is  used  by  the  horse, 
in  lieu  of  hands,  to  wipe  away,  dust,  insects,  &c.  The  eye 
of  the  horse  has  strong  muscles,  attached  to  it,  and  one, 
peculiar  to  quadrupeds,  by  the  aid  of  which  the  eye  may  be 
drawn  back  out  of  the  reach  of  danger.  When  this  muscle 
acts,  the  haw,  which  is  guided  by  the  eyelids,  shoots  across 
the  eye  with  the  rapidity  of  lightning,  and  thus  carries  off 
the  often  ding  matter.  Its  return  is  equally  rapid.  Youatt. 
(Prof.  Youatt  denounces  the  practice  of  cutting  out  the 
haw  as  barbarous,  that  is,  in  ordinary  cases  of  inflammation. 
He  says  that  if  farriers  and  grooms  were  compelled  to  walk 
for  miles  in  the  dust  without  being  permitted  to  wipe  or 
cleanse  their  eyes,  they  would  feel  the  torture  to  which  they 
often  subject  the  horse.) 

Mi'ocENE.  Literally,  less  recant.  In  geology,  a  term  applied 
to  the  rairklle  division  of  the  tertiary  strata,  containing  fewer 
shells  of  recent  species  than  the  Pliocene,  but  more  than  the 
Eocene.  LyeM. 

The  Miocene  is  ap]mrently  the  culminating  age  of  the 
mammalia,  so  far  as  physical  development  is  concerned, 
which  accords  with  its  remarkably  genial  climate  and  exu- 
berant vegetation.  In  Europe  the  beds  of  this  age  present 
for  the  first  time  examples  of  the  monkeys.  Among  carniv- 
orous animals,  we  have  cat-like  creatures,  one  of  which  is  dis- 
tinguished  from  all  modern  animals  of  its  group  by 'the  long, 
saber-shaped  canines  of  its  upper  jaw,  fitting  it  to  pull  down 
and  destroy  those  large  pachyderms  which  could  have  easily 
shaken  ofi"  a  lion  or  a  tiger.  Here  also  we  have  the  elephants, 
the  mastodon,  a  great,  coarsely -built,  hog-like  elephant, 
some  species  of  which  had  tusks  both  in  the  upper  and  lower 
jaw  ;  the  rhinoceros,  the  hippopotamus,  and  the  horse,  all  of 
extinct  species.  J-  ^-  I^a'^^on. 

Morpholog'ical.     That  which  has  relation  to  the  anatomical 


THE    USES   OF    MORPHOLOGY.  245 

conformation  of  parts.  Applied  at  times  to  the  alterations 
in  the  '  form '  of  the  several  parts  of  the  embryo,  in  contra- 
distinction to  'histological,'  which  is  applied  to  the  transfor- 
mation by  which  the  tissues  are  gradually  generated.  In 
comparativa  anatomy  it  is  applied  lo  the  history  of  the  modi- 
fications of  forms  which  the  same  organ  undergoes  in  differ- 
ent animals. 

Morphol'ogy  is  that  branch  of  zoology,  in  its  widest  sense, 
which  treats  of  the  general  form  (not  outline)  and  organiza- 
tion of  animals,  and  the  principles  involved,  as  well  as  the 
correspondence  in  the  various  forms  of  the  several  members 
and  parts,  so  far  as  they  are  comparable  in  any  structural 
characters,  but  entirely  independent  of  the  uses  of  the  parts 
and  organs.  It  thus  contrasts  witli  animal  physiology,  which 
treats  of  the  organization  in  whol  /•,  so  far  as  respects  adapta- 
tion to  surroundings,  as  well  as  the  vai'ious  parts  and  organs, 
so  far  as  their  uses  and  functions  are  concerned.  To  discover 
the  utility  of  organization  in  diverse  animal  forms  and  the 
essential  similarity  in  their  mode  of  evolution,  are  the  prin- 
cipal problems  within  the  province  of  morphology.  Gill. 

Mucous  Membrane  (lining  of  alimentary,  respiratory,  and 
genito-urinary  tracts)  consists  of  mucous  membrane  proper 
and  submucous  tissues.  The  first  consists  of  secretory  tuber- 
cles, follicles,  and  glands  ;  the  second  of  elastic  connective 
tissue  (capillary  blood-vessels  and  nerve-filaments)  by  which 
the  secretory  surface  is  nourished.  Its  free  surface  is  lined 
with  epithelial  cells,  related  to  the  mucous  tissues  beneath  as 
the  epidermic  cells  are  to  the  skin  ;  affords  an  extensive  sur- 
face for  the  great  functional  glandular  processes  of  nutritive 
absorption  and  the  elimination  of  effete  excretory  products. 
Its  special  function  is  to  secrete  mucus,  and  thus  protect  its 
passages  from  the  contact,  attrition,  and  irritation  of  their 
moving  contents.  Mucus  consists  of  water,  mucosine,  and 
salts.  When  rich  in  mucosine,  it  is  viscid  and  tenacious  ; 
when  salines  predominate,  it  is  scarcely  more  than  transuded 
blood-serum.  E.  I).  Hudson,  Jr. 

Musk-Deer,  a  small  deer  of  Central  Asia  ;  a  timid  creature  of 
nocturnal  habits,  and  is  much  hunted  for  its  yield  of  musk, 
which  is  obtained  from  a  sac  beneath  the  abdomen,  on  the 
male  alone.     The  flesh  is  esteemed,  though  that  of  the  male 


246  VOCABULARY. 

is  very  rank  and  somewliat  musky.  It  ranges  from  Siberia 
to  Tonquin.  JohnsDn's  iV.  JJ.  Cyc. 

MuNTJAC,  of  India,  Java,  he,  a  small  deer,  but  little  over  two 
feet  liigli.  The  males  have  small  horns;  the  females  are 
hornless.  Their  flesh  is  excellent.  The  Ciiinese  muntjac, 
like  the  preceding,  is  often  half  domesticated,  and  is  some- 
times bred  in  European  parks.  Johnson's  H.  IT.  Cyc. 

Myl'odo:n,  An  extinct  edentate  animal,  allied  to  the  megathe- 
rium. LyelL 

Nar'whal,  or  Sea-Unicorn.  *  It  is  most  nearly  related  to  the 
white  whale.  Belonging  to  an  order  in  which  many  of  the 
members  never  develop  teeth  at  all,  it,  of  all  animals,  is  sup- 
plied with  a  tooth  altogether  out  of  proportion  to  its  size,  and 
it  is,  moreover,  developed  in  utter  contravention  of  the  rules 
of  hi  lateral  symmetry,  which  in  every  known  case  among 
vertebrates  govern  the  production  of  the  teeth.  In  both 
sexes  the  lower  jaw  is  edentulous.  The  male,  however,  is 
provided,  on  the  left  side  of  the  upper  jaw,  with  a  tusk  from 
eight  to  ten  feet  long.  It  is  straight,  spirally  grooved  ex- 
ternally, and  hollowed  within  into  a  persistent  pulp-cavity. 
On  the  right  side  the  corresponding  tooth  generally  remains 
hidden,  smooth,  and  solid,  within  the  jaw.  In  addition  to 
these,  there  are  two  small  rudimentary  molars  concealed  in 
the  upper  jaw.  The  narwhal,  which  is  considered  one  of 
the  greatest  curiosities  of  natural  history,  attains  to  a  length 
of  fifteen  feet.  Its  single  spiracle  or  blow-hole  is  situated  on 
the  top  of  the  head.  E.  G.  H.  Day. 

Necro'sis,  or  death  of  a  bone,  corresponds  to  mortification  of 
the  soft  structures,  and  is  as  distinct  from  caries  as  mortifica- 
tion is  from  ulceration.  Necrosis  is  divided  into -four  varie- 
ties, namely:  1.  The  scrofulous.  2.  The  superficial,  or  that 
which  involves  the  outer  lamellae,  and  presents  itself  in  the 
flat  and  long  bones.  3.  That  form  which  destroys  the  in- 
ternal part  of  a  bone,  and  in  which  the  outer  shell  is  not  af- 
fected. 4.  That  in  which  the  whole  thickness  of  the  bone 
dies.  W.  Williams. 

O. 

Odontal'gia.     Toothache. 

Odontog'eny,    Generation  or  mode  of  development  of  the  teeth. 


A    DUCK-BILLED    MAMMAL.  247 

Odontog'kaphy.    a  description  of  the  teeth. 

Odon'toid.     Tooth-shaped. 

Odontol'ithos.  a  sort  of  incrustation,  of  a  yellowish  color, 
which  forms  at  the  coronse  of  the  teeth,  and  is  called  '  tartar.' 
It  consists  of  79"  parts  of  phosphate  of  lime,  12i  of  mucus,  1 
of  a  particular  saLvary  matter,  and  7i  of  animal  substance, 
soluble  in  chlorohydric  acid.  A  species  of  infusoria,  '  deutic- 
ola  hominis,'  has  been  found  in  it. 

Odontol'ogy.     An  anatomical  treatise  of  the  teeth. 

Oral.     Relating  to  the  moutn  or  to  speech. 

Oral  EpiTHE'Liu>r.     See  'Epithelium.' 

Orxitho?>hyn'chus.  An  effodient  (dicrgino:),  monotrematous 
mammal,  with  a  horny  beak  resemblino-  that  of  a  duck,  and 
two  merely  fibrous  cheek  teeth  on  each  side  of  both  jaws,  not 
fixed  in  any  bone,  but  only  in  the  o-um  ;  with  pentadactylous 

.  (five-fingered)  paws,  webbed  like  the  feet  of  a  bird,  and 
formed  for  swimming,  and  with  a  spur  in  the  hinder  feet, 
emitting  a  poisonous  liquid  from  a  reservoir  in  the  sole  of  the 
foot,  supplied  by  a  gland  situated  above  the  pelvis,  and  by 
the  side  of  the  spine.  The  animal  is  covered  wdth  a  brown 
fur.  It  is  found  only  in  New  Holland,  and  is  sometimes 
called  Water  Mole.  Bell. 

As  the  name  of  the  order  imports,  the  alimentary,  urinary, 
and  reproductive  organs  open  into  a  common  cloaca,  as  in 
birds ;  mammary  glands  are  present,  secretinfj  milk  for  the 
young,  which  are  born  blind  and  naked ;  there  are  no  prom- 
inent nipples,  and  the  mammary  openings  are  contained  in 
slits  in  the  integument ;  M.  Verreaux  says  the  younp:,  when 
they  are  able  to  swim,  suck  in  the  milk  from  the  surface  of 
the  water,  into  which  it  is  emitted.  Americin  Cyc. 

'Duck-Bill,'  the  English  name  of  the  Ornithorhynchus  par- 
adoxus, found  in  Van  Diemen's  land  and  Australia.  In  its 
bill-like  jaws,  its  spurs,  its  monotrematous  character,  its  non- 
placeutal  development,  and  its  anatomy,  it  appears  to  be  a 
connecting  link  between  birds  and  mammals.  The  Duck-Bill 
is  the  only  animal  of  its  genus.  It  is  about  fifteen  inches 
long ;  it  Climbs  trees  with  facility,  and  digs  burrows,  often 
thirty  feet  long,  in  the  river  bank,  with  one  opening  above 
and  another  below  water.  It  inhabits  ponds  and  quiet 
streams,  swimming  about  with  its  head  somewhat  elevated, 


248  YOC^rBULARY. 

often  diving  for  its  food,  wliicli  consists  of  insects  and  other 
small  aquatic  animals.  Johnson's  N.  U.  Cyc. 

Of  all  the  mammalia  yet  known,  the  Ornithorhynchus 
seems  the  most  extraordinary  in  its  conformation,  exhibiting 
the  perfect  resemblance  of  the  beak  of  a  duck  engrafted  on 
the  head  of  a  quadruped,  Br.  Shaw. 

According:  to  Ernst  H.  Haeckel,  these  animals  "are  be- 
coming loss  numerous  year  by  year,  and  will  soon  be  classed, 
with  all  their  blood  relations,  among  the  extinct  animals  of 
our  globe." 

Os.     A  bone  ;  also  a  mouth. 

Osteol'ogy.     The  part  of  anatomy  which  treats  of  bones. 

Osteo-sarco'ma.  Disease  of  the  bony  tissue,  which  consists  in 
softening  of  its  laminae,  and  their  transformation  into  a  fleshy 
substance,  analogous  to  that  of  cancer,  accompanied  with 
general  symptoms  of  cancerous  affection.  The  word  has  also 
often  been  used  synonymously  with  '  spina  ventosa.' 

O'vAMES  {ovum,  egg).  The  two  organs  in  oviparous  animals 
in  which  the  ova,  the  generative  product  of  the  female,  are 
formed.  They  are  termed  by  Galen  '  testes  muliebres,'  since 
they  are  in  women  the  analogues  of  the  testes  in  men.  The 
ovaries  in  adult  women  are  situated  on  either  side  of  the 
uterus,  in  the  iliac  fossae ;  they  are  included  in  the  two  pel- 
vic duplicatures  of  the  peritoneum,  which  are  called  the 
broad  ligaments.  Each  ovary  is  also  attached  by  a  round, 
fibrous  corJ — the  ovarian  ligament — to  the  side  of  the  uterus, 
and  by  a  lesser  fibrous  cord  to  the  fringed  edge  of  the  Fallo- 
pian oviduct.  The  ovary  is  an  oblong,  ovoid,  flattened  body, 
of  a  whitish  color  and  uneven  surface.  It  is  ^  to  |^  an  inch 
thick,  f  of  an  inch  wide,  and  1  inch  to  1 1-  long ;  it  weighs 
from  1  to  2  drachms.  M  Darwin  Hudson,  Jr. 

Oze'na.  An  affection  of  the  pituitary  membrane,  which  gives 
occasion  to  a  disagreeable  odor  similar  to  a  crushed  bed-bug. 
P. 

Paleontol'ogy.  The  study  of  ancient  beings.  The  science 
which  treats  of  the  evidences  of  organic  life  upon  the  earth 
during  the  different  past  geological  periods  of  its  history. 
These  evidences  consist  in  the  remains  of  plants  and  animals 
imbedded  or  otherwise  preserved  in  the  rocky  s'rita  or  upon 
their  surfaces,  aud  in  other  indications  of  animal  existence, 


footp:unts  ix  the  saxds  of  time.        249 

Buch  as  trails,  footprints,  burrows,  and  coprolitic  or  other 
organic  material  found  in  the  rocks.  Pythagoras,  Plato, 
Aristoile,  and  other  ancients,  allude  to  the  existence  of  ma- 
rine shells  at  a  distance  from  the  sea :  it  was  considered  con- 
clusive evidence  that  the  rocks  containing  them  had  formerly 
been  submerged  beneath  the  ocean.  Am.  Cyc. 

Papil'la.  The  end  of  the  nipple,  or  an  eminence  similar  to  a 
nipple. 

Tlie  minute  elevations  of  the  surface  of  the  skin,  tongue, 
&c.  They  serve  to  increase  the  extent  of  surface  for  vascular 
distribution,  or  subserve  sensitive  or  mechanical  purposes. 
Some  contain  one  or  more  vascular  loops ;  others,  nervous 
elements.  Some  are  surmounted  by  dense  epithelial  fila- 
ments, as  those  wduch  give  the  roughness  to  the  tongue. 

Webster. 

Par'asite.  Parasites  are  plants  which  attach  themselves  to 
other  plants,  and  animals  which  live  in  or  on  the  bodies  of 
other  animals,  so  as  to  subsist  at  their  expense.  The  mis- 
tletoe is  a  parasitic  plant,  the  louse  a  parasitic  animal. 

Pari'etes.  a  name  given  to  parts  w^hich  form  the  inclosure  or 
limits  of  different  cavities  of  the  body,  as  the  parietes  of  the 
cranium,  chest,  &c. 

Parot'id.'  ('About  the  ear.')  The  largest  of  the  salivary 
glands,  seated  under  the  ear  and  near  the  angle  of  the  lower 
jaw.     It  secretes  saliva. 

Pathol' OGY.  The  branch  of  medicine  whose  object  is  the 
knowledge  of  disease.  It  has  been  defined  '  diseased  physiol- 
ogy,' and  '  physiology  of  disease.'  It  is  divided  into  general 
and  special.  The  first  considers  diseases  in  common;  the 
second  the  particular  history  of  each.  It  is  subdivided  into 
internal  and  external,  or  medical  and  surgical. 

Pelvis  The  part  of  the  trunk  which  bounds  the  abdomen 
below. 

Periodonti'tis.  Inflammation  of  the  membrane  that  lines  the 
socket  of  a  tooth. 

Pertos'teum.  The  periosteum  is  a  fibrous,  white,  re.iisting 
medium,  which  surrounds  the  boaes  every  where,  except  the 
teeth  at  their  coronse  (crowns^  and  the  parts  of  other  bones 
that  are  covered  with  cartilage.  The  external  surface  is 
united,  in  a  more  or  less  intimate  manner,  to  the  adjoining 


'2i)0  VOCA'UULAKY. 

parts  by  areolar  tissue.  Its  inner  surface  covers  the  bones, 
wliose  depressions  it  accurately  follows.  It  is  united  to  the 
bone  by  small  fibrous  prolongations,  and  especially  by  a  pro- 
digious quantity  of  vessels,  which  penetrate  their  substance. 
It  unites  the  bones  to  the  neighboring  parts,  and  assists  in 
their  growth,  either  by  furnishing,  at  its  inner  surface,  an 
albuminous  exudation,  which  becomes  cartilaginous  and  at 
length  ossifies,  or  by  supporting  the  vessels  which  penetrate 
them  to  carry  the  materials  of  their  nutrition. 

Petrous,     Resembling  stone  ;  having  the  hardness  of  stone. 

Phlegmon.  Inflammation  of  the  areolar  texture,  accorfepanied 
with  redness,  circumscribed  swelling,  increased  heat  and 
pain,  which,  at  first,  is  tensive  and  lancinating  and  afterward 
pulsatory  and  heavy.     It  is  apt  to  terminate  in  suppuration. 

PiA  Mater  (tender  mother),  so  named  because  it  nourishes  the 
nerve-centers.  The  innermost  covering  of  the  brain  and 
spinal  cord  ;  a  fine  plexus  of  blood-vessels,  dipping  into  the 
brain's  convolutions,  forming  the  velum  interpositum  in  the 
third  and  the  choroid  plexus  in  the  fourth  ventricle.  A 
small  part  (over  the  crura  and  pons)  is  not  very  vascular,  but 
tough  and  fibrous,  while  that  of  the  spinal  cord,  with  Avhich 
it  is  intimately  connected  and  of  w^iich  it  is  the  neurilemma, 
is  still  less  vascular.  It  is  partly  composed  of  longitudinal 
fibrous  bundles,  and  is  abundantly  supplied  with  nerves  and 
lymphatics.  The  tunica  vasculosa  of  the  testes  is  also  called 
pia  mater.  Johnson's  JSf.  JJ.  Cyc. 

PiTU'iTARY.     Concerned  in  the  secretion  of  muscus  or  phlegm. 

Pituitary  Membrane.  The  mucous  membrane  wMiich  lines 
the  nasal  fossa?,  and  extends  to  the  cavities  communicating 
with  the  nose.     It  is  the  seat  of  smell. 

Plas'ma.     See 'Liquor  Sanguinis.' 

Pleistocene.  A  term  used  to  denote  the  newest  tertiary  de- 
posits. JoJinsoji's  N.  JJ.  Cyc. 

Pli'ocene.  In  geology,  the  term  applied  to  the  most  modern 
of  tertiary  deposits,  in  w^hich  most  of  the  fossil  shells  are  of 
recent  species.  Lyell. 

With  regard  to  animal  life,  the  Pliocene  continues  the  con- 
ditions of  the  Miocene,  but  with  signs  of  decadence.  The 
Pliocene  was  terminated  by  the  cold  or  Glacial  period,  in 
which  a  remarkable  lowering  of  temperature  occurred  over 


THE   WOOLLY    nillXOCEKOS.  251 

all  the  northern  hemisphere,  accompanied,  at  least  in  a  por- 
tion of  the  time,  by  a  very  general  and  great  subsidence, 
which  laid  all  the  lower  part  of  our  continent  under  water. 
This  terminated  much  of  the  life  of  the  Pliocene,  and  re- 
placaJ  it  with  boreal  and  arcdc  forms,  some  of  theji,  like  the 
great  hairy  Siba  ian  mammoth  and  the  woolly  rhinoceros,  fit 
successors  of  the  gigantic  Miocane  fauna.         J.  W.  Dawson. 

Pol'ypus.  a  name  given  tj  tumors  which  occur  in  mucous 
membranes  especially,  and  which  have  been  compared  to  cer- 
tain zoophytes.  Polypi  may  fonn  on  every  mucous  mem- 
brane. They  vary  much  in  size,  number,  mode  of  adhesion, 
and  in  dm  ate  nature.  Fibrous  polypi  are  of  a  dense,  compact 
texture  and  whitish  color.  They  contain  few  vessels  and  do 
not  degenerate  into  cancer.  The  scirrhous  or  carcinomatous 
are  true  cancerous  tumors,  painful  and  bleeding. 

Pons  Varolii.  An  eminence  at  the  upper  part  of  the  medulla 
oblongata,  first  described  by  Varolius.  It  is  formed  by  the 
union  of  the  crura  cerebri  and  crura  cerebelli. 

Poste'rior.     Opposed  to  '  anterior,'  which  see. 

Pter'ygoid.  a  name  given  to  two  processes  at  the  inferior 
surface  of  the  sphenoid  bone,  the  two  laminae  which  form 
them  having  been  compared  to  wings. 

Pylou'ic.  That  which  relates  to  the  'pylorus.'  An  epithet 
given  to  different  parts. 

Pylo'rus.  a  'gate,'  a  'guardian.'  The  lower  or  right  orifice 
of  the  stomach  is  called  'pylorus'  because  it  closes  the  en- 
trance into  the  intestinal  canal,  and  is  furnished  with  a  cir- 
cular, flattened,  fibro-mucous  ring,  which  causes  the  total 
closure  of  the  stomach  during  digestion  in  that  organ.  It  is  a 
fold  of  the  mucous  and  muscular  membranes  of  the  stomach, 
and  is  the  '  pyloric  muscle'  of  some  authors. 

Q. 

Quadruma'na.  {Quatuor, '  four,'  and  manus, '  hand.')  A  name 
employed  by  Blumenbach  (in  1791)  as  an  ordinal  designation 
for  the  monkeys,  lemurs,  and  related  types,  man  having 
been  isolated  as  the  representative  of  a  peculiar  or;ler  named 
Bimanus.  The  views  thus  expressed  were  for  a  long  time 
predominant  ;  but  a  closer  study  of  the  structure  of  the  forms 
indicated  by  those  names  has  convinced  almost  all  living 
naturalists  that  they  were  erroneously  separated,  and  the  two 


252  VOCABULAKY. 

types  are  now  generally  combined  in  one  order  named  Pri- 
mates, under  wbicli  head  man  and  the  monkeys  are  com- 
bined together  in  one  sab-order  (Authropoidea),  and  con- 
trasted with  the  lemurs,  which  constitute  another  sub-order 
(Prosimise).  Theodore  Gill. 

K. 

Rectum.  The  third  and  last  portion  of  the  great  intestine.  It 
forms  the  continuation  of  the  sigmoid  flexure  of  the  colon, 
occupies  the  posterior  part  of  the  pelvis,  and  extends  from 
the  sacro- vertebral  articulation  to  the  coccyx  (rump  or  crup- 
per bone),  before  which  it  opens  outward  by  the  orifice  called 
the  'anus.' 

Reg'ime.     Mode  of  livino: ;  government,  administration. 

Reg'imen.  The  rational  and  methodical  use  of  food  and  of 
everything  essential  to  life,  both  in  a  state  of  health  and  dis- 
ease. It  is  often  restricted  in  its  meaning  to  *  diet.'  It  is 
sometimes  used  synonymously  with  hygiene  (health). 

Ru'minant.  a  division  of  animals  having  four  stomachs,  the 
first  so  situated  as  to  receive  a  large  quantity  of  vegetable 
matter  coarsely  bruised  by  a  first  mastication,  which  passes 
into  the  second,  where  it  is  moistened  and  formed  into  little 
pellets  ;  these  the  animal  has  the  power  of  bringing  again  to 
the  mouth,  to  be  rechewed,  after  which  it  is  swallowed  into 
the  third  stomach,  from  which  it  passes  into  the  fotirth, 
where  it  is  finally  digested.  Webster. 

(Several  vv^ell  authenticated  cases  of  human  beings  who 
ruminated  their  food  are  on  record.) 
S. 

Sarco'ma.  Any  species  of  excrescence  having  a  fleshy  consist- 
ence. 

ScHXEiDERiAN  MEMBRANE.     See  *  Pituitary  membrane.' 

Sclerot'ic.  a  heavy,  resisting,  opaque  membrane-,  of  a  pearly 
white  color  and  fibrous  nature,  which  covers  nearly  the  pos- 
terior four-fifths  of  the  globe  of  the  eye,  and  has  the  form  of 
a  sphere  truncated  before. 

Bella  Tur'cica.  (Turkish  saddle.)  A  depression  at  the  upper 
surface  of  the  sphenoid  bone,  which  is  bounded,  anteriorly 
and  posteriorly,  by  the  clinoid  processes,  and  lodges  the  pitu- 
itary gland.  It  is  so  called  from  its  resemblance  to  a  Turkish 
saddle. 


THE   HOUSE,   ASS,   MULE,   QUAGGA.  253 

Septum,  A  part  intended  to  separate  two  cavities  from  each 
other,  or  to  divide  a  principal  cavity  into  several  secondary 
cavities. 

Serous.  Thin,  watery.  Relating  to  the  most  watery  portion 
of  animal  fluids,  or  to  membranes  that  secrete  them. 

Sol'iped.    An  animal  whose  hoof  is  not  cloven ;  one  of  a  group 

of  animals  with  undivided  hoofs;  a  soiid ungulate.     Webster. 

The  family  '  Solipeda '  consists  of  several  species  of  horse, 

namely,  the  ass,  the  mule,  and  the  quagga.  Touatt. 

Sphenoid.     Wedge-shapad. 

Sphenoid  Bone.  An  azygous  (single)  bone,  situate  on  the  me- 
dian line,  at  the  base  of  the  cranium.  It  articulates  with  all 
the  bones  of  that  cavity,  supporting  them  and  strengthening 
their  union.  Its  form  is  singular,  resembling  a  bat  with  its 
wings  extended. 

Spina  Vento'sa.    See  '  Osteo-sarcoma.' 

Styloid.     (A  style,  a  peg,  a  pin.)     Shaped  like  a  peg  or  pin. 

SuBMAX^iLLARY  (from  suh,  'under,'  Tnaxilla,  'the  jaw').  That 
which  is  seated  beneath  the  jaw, 

Suppuka'tion,  Formation  or  secretion  of  pus.  It  is  a  frequent 
termination  of  inflammation,  and  may  occur  in  almost  any  of 
the  tissues.  This  termination  is  announced  by  slight  chills, 
by  remission  of  the  pain,  which,  from  being  lancinating,  be- 
comes heavy  ;  by  a  sense  of  weight  in  the  part,  and,  when 
the  collection  of  pus  can  be  easily  felt,  by  fluctuation.  When 
pus  is  thus  formed  in  the  areolar  membrane,  and  is  collected 
in  one  or  more  cavities,  it  constitutes  an  'abscess.'  If  it  be 
formed  from  a  surface  exposed  to  the  air,  it  is  an  '  ulcer.'  and 
such  ulcers  we  are  in  the  habit  of  establishing  artificially  in 
certain  cases  of  disease. 

Supra.  A  common  Latin  prefix,  signifying  'above.' 
Suture.  A  kind  of  immovable  articulation,  in  which  the  bones 
unite  by  means  of  serrated  edges,  which  are,  as  it  were,  dove- 
tailed into  each  other.  The  articulations  of  the  greater  part 
of  the  bones  of  the  skull  are  of  this  kind. 
Sym'physis,  a  union  of  bones.  The  bond  of  such  union.  The 
aggregate  of  means  used  for  retaining  bones  in  ^itu  (natural 
situations)  in  the  articalations.  The  name  symphysis  has, 
however,  been  more  particularly  appropriated  to  certain  artic- 
ulations, as  the  '  symphysis  pubis,' '  sacro-iliac  symphysis,'  «Sz;c. 


254  TOCAB.ULAKY. 

T. 

Teleosts  (or  Tel-EOSTEi).  The  name  of  tliat  sub-class  of  fislies 
whicli  embraces  the  great  majority  of  living  species,  and  so 
designated  (by  Johannes  Miiller)  on  account  of  the  ossified 
condition  of  the  skeleton  in  all  the  representatives  of  the 
^j.Q^jp_  Theodore  Gill. 

Teratol'ogy.     a  treatise  on  monsters. 

Ter'tiary.  Third ;  of  the  third  formation.  In  geology,  a 
series  of  strata,  more  recent  than  the  chalk,  consisting  of 
sandstones,  clay  beds,  limestones,  and  frequently  containing 
numerous  fossils,  a  few  of  which  are  identical  with  existing 
species.  It  has  been  divided  into  Eocene,  Miocene,  and  Pli- 
ocene, which  sea.  Dana. 

Tikctu'ra  Myrrhs.  (Tincture  of  Myrrh.)  Tonic,  deobstruent 
(removing  obstructions),  antiseptic  (opposed  to  putrefaction), 
and  detergent.  It  is  chiefly  used  in  gargles,  and  is  applied 
to  foul  ulcers,  spongy  gums,  &c. 

Tissue.  By  this  term,  in  anatomy,  is  meant  the  various  parts 
which,  by  their  union,  form  the  organs,  and  are,  as  it  were, 
their  anatomical  elements.  '  Histological  anatomy  '  is  the 
anatomy  of  the  tissues,  which  are  the  seat  of  the  investiga- 
tions of  the  pathological  anatomist.  The  best  division,  in- 
deed, of  diseases  would  be  according  to  the  tissues  mainly 
implicated. 

Tox'ODON.  A  gigantic,  pachydermatous  quadruped,  now  ex- 
tinct, having  teeth  bent  like  a  bow.  Brande. 

Transuda'tion.  (To  sweat.)  The  passage  of  a  fluid  through 
the  tissue  of  any  organ,  wliich  may  collect  in  small  drops  on 
the  opposite  surface,  or  evaporate  from  it. 

Trephine'.  The  instrument  which  has  replaced  the  trepan  in 
some  countries.  It  consists  of  a  simple,  cylindrical  saw,  with 
a  handle  placed  transversely,  like  that  of  a  gimlet;  from  the 
center  of  the  circle  described  by  the  saw  a  sharp  little  per- 
forator, called  the  center-pin,  projects.  The  center-pin  is 
capable  of  being  removed,  at  the  surgeon's  option,  by  means 
of  a  key.  It  is  used  to  fix  the  instrument  until  the  teeth  of 
the  saw  have  made  a  groove  sufficiently  deep  for  it  to  work 
steadily. '  The  pin  must  then  be  removed.  Sometimes  the 
pin  is  made  to  slide  up  and  down,  and  to  be  fixed  in  any 
position,  by  means  of  a  screw. 


MINUTE,    KOD-SIIAPED    PARASITES.  255 

Tro'car.  An  instrument  used  for  evacuating  fluids  from  cavi- 
ties, particularly  in  ascites  (serous  fluid  in  the  abdomen,  or, 
more  properly,  dropsy  of  the  peritoneum),  hydrocele  (watery 
tumors;,  &c.  A  trocar  consists  of  a  perforator,  or  stylet,  and 
a  canula.  The  canula  is  so  adapted  to  the  x^erforator  that, 
when  the  puncture  is  made,  both  enter  the  wound  with  facil- 
ity ;  the  perforator  being-  then  withdrawn,  the  fluid  escapes 
through  the  canula. 

Tubercle.  Miliary  tubercles  are  muiute,  bright,  rounded,  trans- 
lucent particles,  called  granula,  granulations,  kc.  When 
they  coalesce,  forming  larger  bodies  and  undergo  a  change  of 
color  they  are  known  as  crude  or  yellow  tubercles.  As  age 
advances,  the  center  is  apt  to  be  occupied  by  a  giant  cell,  a 
large  multinucleated  body,  whose  boundaries  and  processes 
are  hard  to  define,  because  they  shade  oflT  gradually  into  the 
surrounding  tissue.  They  are  the  result  of  an  inflammatory 
process,  because  they  can  be  produced  by  the  introduction 
of  mechanical  irritants.  In  some  instances  we  have  reason 
to  believe  miliary  tubercles  may  become  organized  and  a 
cure  result.  Tuberculosis  is  hereditary,  and  there  is  some 
good  evidence  to  prove  it  is  contagious ;  it  is  also  inoculable, 
and  "  breeds  true,"  always  producing  its  kind,  if  it  produces 
anything,  but  it  has  not  been  satisfactorily  proved  to  have  a 
specific  virus.  T.  E.  Satterthwcdte. 

(Dr.  Koch  of  Berlin  says  (1882)  tuberculosis  is  caused  by 
minute,  rod-shaped  parasites  (bacilli) ;  that  he  has  inoculated 
animals  with  them,  producing  tuberculosis;  that  he  has 
dried  the  sputum  of  phthisical  patients  for  two  months  and 
has  bred  the  parasites  artificially  for  several  generations 
without  their  losing  the  power  of  inoculation  ;  that  when 
the  sputum  is  dried  the  air  is  infected  ;  that  bovine  and  hu 
man  tuberculosis  are  identical  ;  that  tuberculosis  can  be 
given  to  man  by  the  vaUk  (perhaps  flesh  also)  of  tuberculous 
cows.    The  parasites  are  about  _i_.^th  of  an  inch  in  length.) 

Tu^^IC.     An  envelop  ;  as  the  tunic  of  the  eye,  stomach,  bladder. 

TuRGES'CENCE.  Superabundance  of  humors  in  a  part.  '  Tur- 
gescence  of  bile  *  was  formerly  used  to  denote  the  passage  of 
that  fluid  into  the  stomach  and  its  discharge  by  vomiting. 

Tympanites.  A  flatulent  distention  of  the  belly ;  tympany. 
Also  inflammation  of  the  lining  membrane  of  the  middle  ear. 


^56  VOa^BULARY. 

u. 

Un'gulate.  Shaped  like  a  hoof.  Having  hoofs,  as  ungulate 
quadrupeds.  Webster. 

U'vEA  (from  uvea,  a  grape).  The  choroid  coat  of  the  eye  ;  the 
post:^rior  layer  of  the  iris. 

U'VEOUS.  Resembling  a  grape ;  applied  to  the  choroid  coat  of 
the  eye. 

V. 

Vas'cular.  That  which  belongs  or  relates  to  vessels — arterial, 
venous,  lymphatic — but  generally  restricted  to  blood-vessels 
only.     Full  of  vessels. 

Velum  Pala'ti.     The  soft  palate. 

Ver'tebrje.     The  bones  which  form  the  spinal  column. 

Vis'cus  (plural,  vis'cera).  One  of  the  organs  contained  in  the 
great  cavities  of  the  body  ;  any  one  of  the  contents  of  the 
cranium,  thorax,  or  abdomen  ;  in  the  plural,  especially  ap- 
plied to  the  contents  of  the  abdomen,  as  the  stomach,  intes- 
tines, &c.  Webster. 

Vit'reous.  Of,  pertaining  to,  or  derived  from  glass.  The  vit- 
reous humor  of  the  eye  is  so  called  because  it  resembles 
melted  glass. 

Z. 

Zooi/OGY.  That  part  of  biology  (science  of  life)  which  relates 
to  animal  life,  and,  as  generally  understood,  the  science 
which  treats  of  the  structure,  classification,  distribution,  hab- 
its, and  derivation  of  living  animals.  In  its  broadest  sense, 
however,  zoology  includes  the  structure,  relations,  and  his- 
tories of  extinct  as  well  as  living  forms  ;  but  this  branch  of 
the  science  is  generally  considered  by  itself  under  the  title 
of '  paleontology.'  The  derivation  and  life-histories  of  many 
groujjs  of  animals  have  been  found  written  in  the  .records  of 
the  past,  and  many  mysteries,  not  only  of  relation  but  of 
structure,  have  been  solved  by  going  back  to  find  dwarfed 
organs  in  full  development  and  widely-separated  forms  linked 
together.  The  zoology  of  the  future  will  therefore  include 
the  animal  life  of  both  the  past  and  the  present. 

J.  S.  Newberry. 

Zygomat'ic.     That  which  relates  to  the  zygoma  or  cheek  bone. 


APPENDIX. 


RECENT   DISCOVERIES   OF   FOSSIL  HORSES. 

BY  J.   L.  WORTMAN. 

The  contributions  to  the  knowledge  of  the  extinct  Perisso 
dactyla,"  made  during  the  last  two  or  three  years  in  this 
country,  are  of  an  imj>ortant  character,  since  they  demonstrate 
the  actual  exist'.ince  of  types  heretofore  hypothetically  assumed. 
The  living  representatives,  the  horse,  tapir,  and  rhinoceros, 
constitute  but  a  small  fraction  of  this  large  order  when  com- 
pared with  the  fossil  forms  ah-eady  known.  One  of  these, 
however,  the  horse,  displays  the  most  specialized  structure  to 
be  found  within  the  limits  of  the  order. 

Many  years  have  elapsed  since  the  first  discovery  in  the 
Tertiary  rocks  of  Europe  of  horse-like  remains,  which  are 
regarded  by  paleontologists  in  the  light  of  direct  ancestry  of 
existing  equines.  Since  then  the  discovery  of  the  remains  of 
these  animals  in  the  same  geological  horizons  in  this  country, 
by  Drs.  Hayden  and  Leidy,  has  strengthened  the  belief  in  the 
descent  of  the  horse  from  very  different  ancestral  types.  Entire 
skeletons,  obtained  from  the  '*  bone  beds  '*  of  the  West,  display 

*  Odd-toed.  The  Perissodactyla  may  be  defined  as  mammals  haWng 
both  pair  of  limbs  fally  developed  and  adapteii  for  walking-  or  running, 
the  toes  having  terminal  phalanges,  incased  in  strong  eorneo«s  sheaths, 
developed  as  hoofs.  Tliese  characters,  however,  apply  to  two  other  orders 
also,  the  Artiodaetyla  (cloven-hoofed  or  even  toeil).  and  the  Amblypoda 
(short-footed),  both  of  which,  however,  possess  many  anatomical  differ- 
ences from  the  Perissodactyla,  particulaily  in  the  structure  of  their  hind 
limbs. 


258  APPENDIX. 

their  osteological  characters  to  such  an  extent  as  to  leave  no 

doubt  as  to  the  correct  determinatiou  of  their  true  affinities. 

It  is  much  to  be  regretted,  however,  that  many  of  these 
animals  have  received  diflerent  names  from  different  authors,  a 
fact  specially  conducive  to  confusion  in  the  nomenclature  of  the 
science.  It  appears  that  the  only  way  to  obviate  this  difficulty 
is  by  strict  adherence  to  priority  in  the  employment  of  a  name, 
provided  it  is  accompanied  by  a  competent  description,  and  the 
nse  of  such  characters  as  will  distinguish  the  animal  named 
from  its  nearest  allies.  If  unaccompanied  by  these  differential 
characters,  it  is  a  nomen  nudum,  and  can  have  no  claim  what- 
ever to  rank  with  those  that  have  been  properly  defined.  I 
mention  these  facts  with  the  hope  of  establishing  a  criterion  by 
which  to  judge  which  name  it  is  proper  to  retain  and  which  it 
is  proper  to  discard  ;  and,  to  elucidate  the  subject,  I  will  gives 
the  names  of  a  few  animals  that  have  been  discovered  during 
the  past  forty  years. 

In  1841  Prof.  Richard  Owen  described  the  remains  of  a 
Lophiodon-like*  animal,  from  the  London  clay  of  Eocene  age, 
to  which  he  gave  the  name  Uyracotheiiam.]  Subsequently  he 
described  a  nearly  allied  genus,  from  the  same  deposit,  under 
the.  nsime  Pliolophus.X  In  Ryracothcrium  the  molar  and  pre- 
molar teeth  are  different,  both  above  and  below.  In  PUolophus 
the  last,  or  fourth  inferior  premolar,  is  like  the  first  true  molar, 
a  character  which  separates  the  two  genera  satisfactorily.  The 
specimens  described  by  Prof.  Owen  do  not  display  clearly  the 
number  of  digits  either  possessed,  but  he  expresses  the  opinion 
that  Pliolophns  has  three  toes  on  the  posterior  limbs. 

*  The  Lophiodons  were  first  described  by  Cuvier.  They  were  allied  to 
the  tapir.  They  derive  their  name  from  the  t-tructure  of  the  true  molars, 
which  have  their  crown?  crossed  transversely  by  two  crests  or  ridges  of 
dentine,  covered  with  a  layer  of  enamel.  The  last  loM-er  molr.r  has  also  a 
small  posterior  lobe.  The  premolars  are  more  simple  in  structure  and 
compressed,  rcsemblim;  the  first  premolars  of  the  tapir.  The  upper  molars 
also  resemble  those  of  the  tapir,  but  approach  in  some  respects  those  of 
the  rhinoceros.  The  diastema,  or  toothless  interval  between  the  canine 
and  premolar  teeth,  was  much  shorter  than  in  the  tapir.  Several  species 
have  been  described  from  the  Eocene  of  France  and  England,  but  little  is 
known  of  the  skull  or  skeleton.  No  true  Lophiodon  is  yet  certainly  knowa 
In  this  country. — O.  C.  Manh. 

t  Transactions  London  Geological  Society,  1841,  pp.  203-20B. 

^  Loc.  Cit.,  pp.  51-72,  18.58. 


CONFUSIOiq^    IX    l^OMENCLATURE.  259 

In  1872  Prof.  O.  C.  Marsh  found  the  remains  of  an  animal  in 
this  country  iu  deposits  of  Eocene  age  to  which  he  applied  the 
name  Orohi2ipu8.^  This  genus  was  originally  founded  on  the 
molar  teeth,  which  he  compared  with  those  of  Anchitherium. 
He  subsequently  ascertained  that  it  possessed  four  toes  on  the 
anterior  and  three  on  the  posterior  limbs. f  He  also  proposed  an- 
other genus  under  the  name  of  Bohipjjus,  :j:  which  he  compared 
witli  Orohippiifi,  stating  that  the  last  inferior  premolar  is  like 
the  first  true  molar,  a  character  which  at  once  distinguishes  it 
from  Hi/racotherium.  As  he  assigns  no  other  dental  characters 
to  this  genus  sufficient  to  separate  it  from  Pliolojjhus,  with 
which,  according  to  his  description,  it  otherwise  agrees,  and  as 
the  digital  formula  in  the  Lophiodons  generally  is  4—3,  the 
two  names  must  be  regarded  as  synonymous.  This  may  like- 
wise he  said  of  the  genus  Orotherium,%  which  Prof.  Marsh 
distinguishes  by  the  bifid  condition  of  the  antero-iuternal  lobe 
of  the  inferior  molars.  This  character  is  also  ascribed  to  a 
number  of  molar  teeth  discovered  by  Dr.  Joseph  Leidy  in  the 
Bridger  Eoc 'ue,  which  he  referred  to  the  genus  Lo-pMotlierium, 
a  near  ally  of  P//ry/6|;9Av.s.  But  as  this  is  a  character  of  very 
doub'ful  generic  value  in  this  group  of  animals,  these  names 
must  be  regarded  as  synonymous  with  Pii-dophus. 

Assuming  then  that  the  most  generalized  form  in  the  ancestry 
of  the  hors3  hitherto  known  was  Hyracotherium,  with  a  digital 
formula  of  4 — 3  and  teeth  of  the  Lophiodon  pattern,  we  are 
now  prepared  to  take  a  step  backward  to  the  primitive  five-toed 
ancestor,  Phenacodns.  But  before  entering  on  a  discussion  of 
this  interesting  form,  it  is  necessary  to  mention  the  discovery 
of  another  genus,  from  the  Lower  Eocene  beds  of  Wyoming, 
which  proves  to  be  a  near  ally  of  Hyracotherium.  This  genus 
Prof.  Cope  calls  Systemodoii,\  and  assigns  as  his  reasons  for 
separating  it  from  Hyracotherium  the  circumstance  that  it  dis- 

*  Ameiican  Journal  Science  and  Arts,  1872. 

t  Loo.  Cit.,  p.  247,  1874. 

X  Loc.  Cit.,  Nov.,  1876.  The  genera  Orohippu?,  Eohippus,  Miohippus, 
and  Pliohippus  have  not  in  my  estimation  been  distinguished  from  genera 
previously  described  ;  hence  my  reasons  for  adopting  names  more  in 
accordance  with  the  prevailing  nomenclature  of  the  science. 

§  Loc.  Cit.,  1872. 

II  American  Naturalist,  1831,  p.  1018. 


2G0  APPENDIX. 

plays  no  diastemata  (spaces)  beliind  tlie  superior  canines,  while 
in  tlie  latter  there  are  two.  This  fossil  (from  New  Mexico)  was 
first  described  by  him  under  the  name  Ilyracotlierium  tapiri- 
num,  but  the  discovery  of  better  specimens  demonstrates  its 
claim  to  the  rank  of  a  new  genus. 

PHENACODUS. 

Phenacodus,  one  of  the  most  imi^ortant  of  recent  paleon- 
tological  discoveries,  was  first  made  known  by  Prof,  Cope  in 
1873,"  from  several  molar  teeth  which  he  obtained  from  the 
New  Mexican  Wasatch.  Its  systematic  position  in  the  mam- 
malian class  was,  however,  involved  in  considerable  uncertainty 
till  the  discovery  of  the  greater  part  of  the  skeletons  of  two 
distinct  species  of  this  genus  by  the  writer  in  the  Wyoming 
Wasatch  during  the  summer  of  1881,  which  aflPorded  Prof. 
Cope  the  means  of  determining  its  true  position  and  elucidat- 
ing the  many  important  and  interesting  points  its  osteology 
teaches.f     It  possesses  five  w^ell  developed  toes  in  functional 

*  Paleontological  Bulletin,  No.  17,  Oct.  1S73,  p.  3. 

t  I'rior  to  the  discoverv  of  these  skeletons  no  characters  had  been  found 
among  the  Ungulata  -which  mdicatc  a  gi'oup  connecting  the  Perissodactyla 
with  the  elephants  and  hyrax.*  But  it  is  now  necessary  to  create  a  new 
order,  which  Prof.  Cope  designates  the  ConGylarthra.  (Paleontological 
Bulletin,  No.  .04.  Dec.  18S1,  p.  17T).  The  characters  on  which  this  division 
reposes  are  found  in  the  carpus  and  the  astragalus  (hock  or  ankle  bone) 
and  their  manner  of  articulation.  The  Peri^sodactyla  are  distinguished  by 
the  fact  that  the  scaphoid  articulates  with  two  bones  below,  and  the  astra- 
galus articulates  inferiorly  by  two  nearly  flat  facets  with  the  cuboid  and 
navicular  bones.  They  are  divisible  into  ten  families,  including  forty-eight 
genera,  variously  distributed  throughout  geologic  time  ;  but  as  only  four 
of  these  families  concern  us  for  the  present,  I  will  spare  the  memory  of  the 
reader  by  not  discussing  the  classification  of  the  others.  The  first  to  which 
attention  may  be  directed  is  the  Lopldodontidx,  embracing^  eight  well'  de- 


*  A  gray-haired,  rabbit-sijced  pachyderm,  with  4  toes  on  the  forefeet,  .3 
on  the  hind,  a  mere  tubercle  for  a  tail,  molars  resembling  (in  miniature) 
those  of  the  rhinoceros,  2  large,  trian;rular,  curved,  tuslv-like  incisors  in  the 
upi)er  jaw,  and  4  straight  ones  in  the  lower.  Cuvier  savs  the  upper  jaw,  in 
youth,  has  2  small  canines,  but  Mnrsh's  dental  formula  is:  Incisors.  1 — 2, 
1—2:  canines.  0—0,  0—0;  premolars,  4—4,  4—4:  molars,  3—3,  3— 3".34. 
There  are  several  species,  the  African  being  able  to  climb  a  tree.  The 
Cai)e  hyrax  is  called  the  rock-baager  or  rocl-rabUt.  The  hyi-ax  was  long 
classed  among  the  r.  dsnts,  and  was  also  called  a  miniature  rhinoceros. 
There  are  various  athniries  between  the  elephant  and  some  rodents — (1)  in 
the  size  of  the  tusks  :  (2)  in  the  molars  being  often  formed  of  parallel  lam- 
inae ;  (3)  in  the  form  of  several  of  then-  bones. 


RELATION  OF  PHEXACODUS  TO   AMELYPODA.      261 

US3  on  all  the  feet,  of  which  the  first  is  the  smrJlcst ;  the 
median  is  the  largest  aud  is  symmetrical  within  itself.  The 
feet  are  considerably  shortened  and  were  probably  semiplanti- 
grade ;  in  fact  the  feet  of  this  animal  constitute  an  approach 
to  the  Amblypoda*     The  dental  formula  is :     Incisors,  3—3, 

fined  genera,  which  arc  not  positively  known  to  have  existed  later  than 
the  upper  Eocene  epoch.  It  may  be  recognized  \,1)  by  the  possession  of 
four  toes  on  the  anterior  and  three  on  the  posterior  limbs  ;  (2)  by  the 
molar  and  premolar  teeth  being  different ;  (3)  by  the  non-separation  of  the 
anterior  and  posterior  external  cusps  of  the  superior  molars  by  an  external, 
rib-like  pillar.  The  next  family  is  the  Chalicothenidce,  to  which  ten  genera 
are  referred.  The  digital  formula  is  the  same  as  in  the  Lophioilontidce.  as 
is  also  the  relation  of  the  molar  and  premolar  teeth.  The  only  distinction 
is  found  in  the  separation  of  the  anterior  and  posterior  external  lobes  by  a 
vertical  ridge.  The  remains  of  this  family  range  from  the  lower  Eocene  to 
the  middle  Miocene.  The  third  family  is  the  Pateotheriidce,  having  three 
toes  on  each  foot.  The  molars  and  premolars  are  alike,  and  the  inferior 
molars  possess  perfect  double  crescents.  The  fourth  family  is  the  Equidce, 
in  which  the  digital  formula  is  reduced  to  one  toe  on  each  foot.  The  mo- 
lars and  premolars  are  alike  and  highly  complex  in  structure.  It  is  to  this 
family  that  all  the  existing  horses  belong,  and  it  has  been  traced  as  far 
back  as  the  upper  Miocene  strata.  The  CondyloMJira,  on  the  other  hand,  are 
effectually  separated  from  the  Feri'SOdactyla  by  the  non-alternating  posi- 
tions of  the  carpals  and  by  the  possession  of  an  astragalus  whose  distal  face 
is  convex  in  every  direction,  as  in  the  carnivora,  and  unites  with  the  navic- 
ular alone.  These  families  are  the  Phenacodontidce  and  Memscotheriidc^ 
whose  remains  have  been  found  so  far  only  m  the  lower  Eocene  deposits 
of  this  country.  It  is  interesting  to  note  that  they  are  the  most  generalized 
of  any  known  Pcrissodactyla  and  supply  a  link  long  sought  in  the  evolu- 
tion of  the  later  and  more  specialized  forms  of  this  order. 

-  There  has  probably  been  no  discovery  among  the  ungulates  since  the 
finding  of  the  Amblypoda  that  has  proved  equal  in  interest  and  importance 
to  the  discovery  of  this  group  (the  Phenacodontidce).  The  descent  of  all 
the  ungulates  from  the  A?nblypoda'has  been  hckl  by  Prof.  Cope  for  some 
time,  but  that  it  took  place  from  any  known  genera  of  this  order  the  com- 
paratively specialized  condition  of  the  teeth  of  the  latter  distinctly  forbids. 
This  moderate  complexity  of  the  teeth  among  Eocene  mammals  is  a  strik- 
ing exception,  especially  when  arsociated  with  such  a  low  grade  of  organi- 
zation of  other  parts  as  we  find  in  these  animals.  The  explanation  of  this 
fact  must,  in  my  judgment,  be  sought  for  in  their  large  size  and  in  ths  pos- 
session of  powerful  canine  teeth,  which  insure  them  greater  immunity  from 
the  attacks  of  fierce  caniivorous  contemporaries.  With  these  means  of 
defense,  they  could  take  up  their  abode  where  food  better  adapted  to  their 
wants  was  furnished.  Hence  we  can  with  perfect  consistency  look  for 
a  rapid  modification  of  these  organs,  accompanied  by  slight  change  in 
others.  In  order  to  make  the  connection  complete  between  them  and  the 
Phenacodonts,  there  should  yet  be  found  an  Amblypod  with  bunodont 


262 


ABPEXDIX. 


3 — 3;  canm3s,  1—1,  1 — 1  ;  premolars,  4 — 4,4 — 4;  molars,  3 — 3, 
3 — 3  =  44  ;  that  is  44  fauctionally  developed  teeth.  The  molars 
are  of  the  simple  four-lobed  pattern,  resembling  in  this  respect 
the  suilline  Artiodactyla  or  hotrs  and  peccaries ;  in  fact  on  this 
aiccount  it  is  a  matter  of  some  surprise  that  the  animal  should 


molars,  reduced  canines  and  a  more  elongated  foot.  An  approach  to  ibis 
condition,  as  far  at  least  as  the  molars  are  concerned,  is  found  in  a  new 
form  recently  described  by  Prof.  Cope  under  the  name  Manteodon  (pro- 
pliecy  tooth).  The  Arnblyimla,  says  Prof.  Cope  in  his  Report  on  Capt. 
Wheeler's  Survey  (W.  lOOih  Mer.,  Pt.  ii,  Vol.  IV,  p.  233),  are  as  yet  con- 
fined to  the  Eocene  peiiod  exclusively,  and  are  found  both  in  Europe  and 
this  country.  In  points  of  affinity  to  the  hoofed  orders  generally  they 
occupy  an  interesting  and  important  position,  being  in  all  probability  the 
oldest  and  affording  the  most  generalized  condition  known  among  the 
ungulates.  The  brain  capacity  is  exceedingly  small  in  proportion  to  the 
size  of  the  other  parts  of  the  skeleton,  and  from  casts  made  from  the  brain 

case  itself  we  are  warranted 
in  assigning  these  animals 
a  position  among  the  low- 
est mammalia;  they  are 
lower  in  brain  development 
even  than  any  of  the  Mar- 
sripials.  The  feet  are  very 
short,  are  provided  with 
five  fully  developed  toes, 
and  have  their  entire  plan- 
tar and  palmar  surfaces  ap- 
plied to  the  ground,  as  in 
the  modern  bears.  The  as- 
tragalus is  greatly  flattened 
from  above  downward,  and 
is  primitive  and  character- 
istic. It  displays  on  irs  in- 
ferior surface  flattened  ar- 
ticular facets  for  both  na- 
vicul.ir  and  cuboid  bones 
which  share  the  articula- 
tion about  ccjually.  Onthe 
superior  part,  the  surface 
articulating  with  the  tibia 
is  almost  flat,  a  condition 
■which  must  have  lendered 
the  ankle  joint  capable  of 
very  little  movement,  and 
giving  to  these  animals  a  peculiarly  awkward  and  shambling  gait.  It  is 
not  dTfficull  to  perceive  that  these  small-brained,  five-toed,  and  plantigrade 
Amblypoda  could  easily  have  furnished  a  starting  point  for  both  the  Artio- 
dacUjla  and  PerUsodactyla,  and,  as  we  have  good  reasons  to  believe,  did 
give  origin  to  the  Proboscidea  or  elephants. 


iglU  hind-foot  of 


species  ofCorvpliodon  (Amblvpod). 
n-iturul  .ize  (Cop.-). 


HOUSES  WITH  TEETH  SIMILAU  TO  REPTILES'.     2G3 

turn  out  not  to  belong-  to  the  snillincs.  "But  when  the  evi- 
dence of  derivation  drawn  from  other  sources  is  considered, 
and  the  geological  period  is  taken  into  account,  the  structure 
of  the  teetli  is  preeminently  in  accordance  with  the  expecta- 
tions of  the  evolutionist.  It  is  important  to  notice  in  this  con- 
nection that  Prof.  Cope  ventured  the  prediction  in  1874*  that 
the  quadritubercular  or  four-lobed  bunodont  f  molar  was  the 
primitive  pattern  in  which  the  more  complicated  selenodont  1^ 
molar  of  the  later  ungulates  had  its  origin.  That  this  predic- 
tion is  now  proved  there  can  be  no  question,  and  the  passage 
from  this  simple  type  of  tooth  to  the  highly  complicated  forms 
illustrated  in  this  article  has,  I  think,  been  close  and  consecu- 
tive and  intimately  associated  with  reduction  in  digits. 

The  Phenacodontidse  present  considerable  variety  as  far  as 
their  family  is  at  present  known.  Prof.  Cope  has  described 
five  genera,  as  follows:  Phenacodus,  Anacodon,  Protogonia, 
Periptycbus,  and  Anisonchus.  Tlie  first  two  are  from  the 
Wasatch  horizon,  while  the  last  three  were  derived  from  the 
underlying  Purco  beds.  Periptychus  shows  a  peculiar  sculp- 
turing of  the  outside  of  the  molar  teeth,  similar  to  that  seen  in 
many  reptiles,  and  is  the  only  mammal  known  to  possess  it. 
The  molars  of  Anacodon  lack  distinct  tubercles,  a  character 
which  assigns  it  the  lowest  position  in  the  family.  Phenacodus 
approaches  nearest  to  the  Lophiodons  in  dental  character  and 
is  taken  for  illustration.  As  all  but  Phenacodus  and  Peripty- 
chus are  known  from  their  teeth  only,  it  may  be  necessary  on 
the  discovery  of  the  character  of  their  feet  to  refer  them  to  new 
families.  The  definition  of  the  family  given  by  Prof.  Cope  is 
as  follows :  Molar  teeth  tubercular  ;  molars  and  premolars 
different ;  fis^e  toes  on  ail  the  feet.§ 

MENISCOTHERIUM. 

The  Meniscotheriidse  has  been  recently  established  for  the 
reception  of  the  single  genus  Meniscotherium,  discovered  by 

*  Journal  Academy  of  Natural  Sciences,  Philadelphia. 

t  Teeth  of  simple  s^tructure,  with  short  crowns  and  low,  blunt  tubercles 
ou  their  fice. 

X  Teeth  of  complicated  strncti>re,  with  high  and  uniformly  broadened 
crowns,  the  face  presenting  a  complex  folding  of  the  enamel  plates. 

§  Paleontological  Bulletin,  No.  34,  Dec,  1881,  p.  118, 


2G4  APPEKDIX. 

Prof.  Cope-  in  tlie  Wasatch  beds  of  New  Mexico,  and  described 
by  him  in  his  report  to  Captain  Wheeler,  already  cited.  It 
was  formerl>-  arranged  in  the  GhaUcotheriidm,  near  Chalicothe- 
riani,  with  which  it  agrees  in  all  essential  dental  characters. 
The  recent  discovery  of  the  bones  of  the  feet  shows  that  they 
display  the  characteristic  peculiarities  of  the  Condylarthra,  to 
which  group  it  mast  be  referred.  Its  digital  formula  is 
unknown,  hence  we  must  rely  on  the  specialized,  crescentoid 
pattern  of  the  molars  for  the  family  definition.  It  is  proper  to 
remark  here  that  reduction  in  digits  in  the  Perissodacty la  is 
usually  accompanied  by  specialization  of  the  molar  teeth.  In 
this  case,  therefore,  I  would  venture  the  prediction  that  its 
digital  formula  will  be  found  to  be  4—3,  with  the  outer  toes 
somewhat  reduced.  Tiie  value  of  the  digital  formula  as  a 
character  in  the  definition  of  the  families  of  the  Perissodactyla 
i3  of  hi.irh  standard.  This  may  likewise  be  said  of  the  rela- 
tion of  the  molar  and  premolar  teeth,  but  in  a  less  degree. 
The  tubercular  or  crescentoid  structure  of  the  molars,  however, 
is  capable  of  such  intergradation,  which  increase  of  our  knowl- 
edge demonstrates,  that  it  must  be  accepted  as  provisional 
only,  and  not  entitled  to  rank  equal  in  value  to  either  of  the 
other  two  characters  in  defining  the  family. 

The  genealogy  of  the  horse  as  now  indicated  is  as  follows ; 


Equus,  Equus, 

Protohippus,  Hippotherium, 

Anchippus,     Paloplotherium, 
Anchitherium, 
Mesohippus, 
Lambdotherium-, 
Hyracotherium, 
Svstemodon. 


Perissodactyla 


Amblypoda,  Hyodonta  (Cope). 


Condylarthra  -  \  Meniscothcrium, 

(  Phenacodus. 


KATUIiE  S   METAM0KPH03LS. 


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APPENDIX. 


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TEETH    FROM    PHE^^ACODUS   TO    EQUUS.  207 

1— Left  upper  molar  of  a  species  of  Phenacodus,  nat.  size  (Cope)  ac-  is 
theantei-o-extcrna],;jethe  postero-estcriKil.  cd  the  amero- internal  and  pi 
the  postero-iuternai  lobes  respectively.  They  are  low  and  obtuse  and  con- 
stitute the  principal  cusps  of  the  crown,  ace  and  pec  are  the  anterior  and 
posterior  cross  crests ;  they  are  rudimentary  and  represented  by  isolated 
tubercles  in  this  animal,  but  are  developed  into  important  structures  in  the 
more  specialized  genera,  y  (the  lobe  is  drawn  too  large)  is  the  rudimental 
external  rib  separating  the  antero  and  postero-esternal  cusps.  An  antero- 
basai  lobe  arising  as  an  outgrowth  from  the  cingulum  or  ledge  surrounding 
the  base  of  the  crown  is  strongly  marked  iu  some  genera. 

2.— Left  lower  molar  of  same.  nat.  size,  z  represents  a  low,  indistinct- 
ly marked  lidge,  passing  from  the  postero-external  to  the  antero-internal 
cusps  pe,  ai.  The  antero-internal  cusp  ai  is  sometimes  double,  h  is  the 
heel,  which  is  so  strong  in  the  last  molar  as  to  be  called  a  fifth  lobe.  It  is 
connected  by  a  faint  ridge  with  the  postero-external  cusp  2)e.  The  four 
principal  cusps  ae.pe,  ai,  pi  hold  the  same  relation  to  the  crown  as  m  the 
upper  molar. 

3.— Right  upper  molar,  of  a  species  oi  Lambdolherivm,  in  which  the  an- 
tero and  postero-external  cusps  ae,pe  are  separated  by  an  external  vertical 
ridge,  y  ;  nat.  size  (Cope). 

4.— Last  lower  molar  (left  side),  of  same  ;  nat.  size.  The  antero-in- 
ternal lobe  is  divided  into  two  distinct  tubercles,  ai,  ai';  the  ridge  k  is 
strong  and  prominent.  The  breadth  of  the  tooth  is  accounted  for  by  the 
fact  that  it  is  the  last  molar,  the  first  and  last  molars  being  about  a  third 
broader  than  the  others.  The  teeth  are  of  a  more  complicated  pattern  than 
those  of  Phenacodus.  It  is  important  to  notice  that  while  the  teeth  of  the 
lower  Eocene  genera  of  this  family  (Lambdolherium  and  Paleosyopous)  re- 
semble  very  strongly  the  teeth  of  the  loM^er  forms  of  the  Lophiodons  in  the 
shortness  of  their  crowns  and  approach  to  the  bunodont  type,  the  latter 
possess  longer  cusps  and  simulate  the  selenodont  forms  iu  the  crescentic 
section  of  some  of  them. 

5.— Left  upper  molar  of  Anchitherium  aureliauense,  nat.  size  (Gaudry), 
The  four  principal  cusps  a^  pe,  ai,  pi  are  considerably  lengthened  and  con- 
nected by  high  ridges,  ace,  pec,  which  pass  in  an  oblique  direction  across 
the  crown.  The  elevation  of  the  cusps  and  crests  give  increased  depth  to 
the  valleys.  The  anterior  basal  lobe  is  reduced  and  the  external  rib  y  is 
strong.    The  crown  is  further  complicated  by  the  addition  of  the  lobe  I. 

6.  -Right  upper  molar  of  a  species  of  Hippofherinm.  The  valleys,  which 
are  deepened  by  the  lengthening  of  the  cusps  and  ridges,  are  filled  by  a 
thick  deposit  of  cement,  but  the  cement,  as  the  cut  shows,  has  been  re- 
moved. The  points  of  the  cusps  and  ridges  are  tinworn.  The  four  princi- 
pal lobes  ae,  pe,  ai,  pi  hold  about  the  same  relation  to  each  other.  The 
cross  crests  ace,  ijcc  have  their  obliquities  increased, and  the  anterior  bends 
around  on  the  inner  part  of  the  face  and  becomes  confluent  with  the  pos- 
terior ridge  ijcc.  The  lobe  I,  which  is  conic  in  Anchitherium,  is  elongated 
in  n  transverse  direction  to  the  crown,  so  as  to  close  the  posterior  valley 
and  join  the  posterior  external  cusp^e  with  the  posterior  crest  pec.  Addi- 
tional vertical  pillars  are  developed  on  the  cross  ridges.    The  teeth  resem- 


268  APPE^^DI 

ble  those  of  the  horse  very  strongly,  the  cro-»vns  of  the  incisors  shovring 
the  peculiar  invagination  s^een  in  the  incisors  of  the  horse. 

7.— Left  Jower  molar  oi  Hippoi.herivni  gracile..  three-fonrths  natural  size 
(Gauciry).  The  lobe  aV  is  now  completely  separated  and  the  ridge  k  rises 
to  a  level  with  the  other  cusps.  The  heel  h  is  also  elevated  and  connected 
by  a  strong  ridge.  The  filling  up  of  tlie  valleys  by  a  deposit  of  cementum 
and  the  consequent  attrition  in  mastication  produce  a  marked  change  iu 
appearance  from  that  seen  in  Anchitherium,  but  by  close  ob:.er\ation  the 
strictest  homology  is  seen  to  exist. 

8.— Left  upper  molar  of  a  species  of  Eqnvs  (modem  horse)  natural  size. 
The  internal  lobes  ai  iii  are  connected  with  the  cross  ridges  ace,  JKC.  The 
only  difference  of  generic  value  between  Equm  and  Ilippiclium  (a  near  rela- 
tive of  the  liorse)  is  seen  in  the  relative  size  of  the  antero  and  postero-in- 
ternal  lobes  ai.pi ;  in  Equus  ai  is  greatly  enlarged  and  somewhat  flattened; 
iu  Hippidium  the  lobes  are  almost  equal. 

What  has  caused  these  chanpres  ?  In  regard  to  tooth  struc- 
ture generally,  Mr.  J.  A.  Ryder  has  given  us  a  most  excellent 
treatise  "On  the  Mechanical  Genesis  of  Tooth  Forms,"*  in 
^vhich  he  shows  that  the  jaw  movements  of  animals  are 
intimately  related  to  the  modification  of  the  component  lobes, 
crests,  and  ridges  of  the  crowns  of  the  molar  teeth.  He  also 
points  out  that  the  restricted  jaw  movements,  in  which  the 
mouth  is  simply  opened  and  closed,  are  associated  with  the 
bnnodont  molar  ;  that  the  various  kinds  of  excursive  mandib- 
ular movements  have  been  developed  progressively;  "that  as 
these  movements  have  increased  in  complexity  there  has  been 
increase  in  the  complexity  of  the  enatnel  foldings." 

If  we  attempt  to  apply  these  facts  to  the  ancestry  of  the  horse, 
it  is  by  no  means  difficult  to  perceive  that  gradual  change  of 
habitat,  causing  a  corresponding  change  in  diet,  would  also 
compel  areater  and  greater  mobility  of  the  mandibttlar  articula- 
tion for  proper  trituration  of  the  new  food.  The  movements  of 
the  lower  jaw  in  these  animals  have  assumed  a  lateral  direction, 
which  affords,  as  I  believe,  a  sufficient  explanation  for  the 
broadenincT  of  the  crowns  and  the  lateral  flattening  of  the  cusps. 
The  obvious  effect  of  force  continually  applied  in  this  direction 
would  be  to  wrinkle  the  enamel  covering  of  the  ctisps  and 
ridges,  thereby  ])roducing  the  accessory  pillars  seen  in  the 
higher  types.  By  this  method,  I  believe,  a  more  and  more 
complex  grinding  surface  has  been  produced. 

*  Proceedings  Academy  Natural  Sciences,  Philadelphia,  1878. 


CAUSE    OF    DIGITAL    REDUCTIOX.  2C9 

The  cause  of  digital  reduction  is  another  interesting  inquiry. 
Bunodouts  as  a  rule  are  dwellers  in  swamps  and  forests  and 
live  on  nuts,  berries,  and  roots.  If  they  are  compelled  to  for- 
sake their  natural  habitat  and  live  in  the  open  field,  either 
modification  or  extinction  will  follow.  Once  in  the  open  field 
speed  becomes  a  desideratum  as  a  condition  of  safety,  and  the 
foot  with  a  reduced  number  of  digits  possesses  many  advan- 
tages over  the  poly  dactyl  e  one. 

Prof.  Cope  has  shown  {American  Naturalist,  April,  1881) 
that  in  plantio^rads  quadrupeds  the  extremities  of  the  toes  are 
arranged  in  a  semicircle,  when  they  are  all  applied  to  the 
ground.  In  the  act  of  running  the  L_cl  and  wrist  are  raised, 
throwing  the  weight  of  the  body  on  the  median  digits.  An 
infinite  repetition  of  this  posture  in  digitigrade  animals  unable 
to  withstand  the  attacks  of  their  enemies  and  whose  only 
escape  was  in  flight,  the  strengthening  of  the  median  digits. 
and  the  consequent  reduction  of  the  outer  ones,  would  follow 
according  to  the  law  of  use  and  disuse  of  parts.  This  subtrac- 
tion of  toes  has  progressed  step  by  step  until  the  modern  one- 
toed  horse  has  been  reached. 

In  summing  up  an  article  in  the  Kansas  City  Review  of  Science 
and  Industry,  Mr.  Wortman  says : 

"I  dare  say  that  if  all  the  intervening  individuals  between 
Phenacodus  and  Equus  could  be  produced  classification  would 
be  utterly  impossible,  so  insensible  would  be  the  gradation." 

The  forms  already  known  appear  to  point  to  the  inevitable 
conclusion  that  the  modern  horse  is  the  product  of  the  slow 
but  improving  processes  of  evolution,  wdiich  are  still  in  opera- 
tion, and  are  being  aided  by  all  the  skill  known  to  modern 
science.  A  discussion  of  the  subject  is  almost  superfluous,  for 
the  illustrations,  like  deeds,  speak  louder  than  words. 

Note.—Vlmj  (B.C.  23)  says  Caesar  had  a  5-toecl  horse  (the  forefeet),  which 
was  represented  in  his  (Plin}''s)  day  hy  a  statue  ;  also  that  Euigeces  says  the 
Bahylonians  had  a  series  of  observations  on  the  stars  for  a  period  of  T20,000 
years,  inscribed  on  baked  bricks.  B^rosus  and  Critodemus  say  490,0C0. 
'CV^ol.  ii.  pp.  221-317.)  Baked  bricks  liave  been  found  buried  in  the  valley 
of  the  Nile  at  a  depth  to  require  the  annual  deposits  of  that  river  for  9,000 
years  (72  feet.)  May  they  not  some  day  be  valuable  aids  to  science  as  well 
as  history  ?    Their  stories  can  be  better  imagined  than  described 


270  API^EXDIX. 


THE   VIEWS    OF   AN    EVOLUTIONIST. 

The  following  "review"  of  Horses'  Teeth,  written  by- 
Mr.  R.  M.  TuTtle  for  Johnstons'  Bental  Miscellany,  contains  so 
mncli  of  interest  on  the  subject  of  evolution  that  I  tliink  no 
apology  necessary  for  inserting  it,  here  instead  of  putting  it 
among  the  other  press  reviews  at  the  conclusion  of  the  volume  : 

"  The  author  of  this  work  modestly  suggests  that  it  may  be 
of  value  to  the  veterinary  professiou  and  also  to  horsemen  and 
farmers.  We  have  no  hesitation  in  going  further  and  atiirm- 
ing  that  it  contains  much  of  an  instructive  and  interesting 
character  for  dentists,  and  all  scientific  and  thoughtful  men. 
The  day  has  gone  by  when  humanity  laughed  or  grew  angry 
(according  to  its  temper  at  the  moment)  at  the  mere  stiggestion 
that  man  has  any  relationship  with  the  lower  animals  beyond 
their  submission  to  his  will  and  his  right  to  lead  them  to  the 
slaughter-house.  The  movement  of  thought  in  the  direction 
of  Evolution  is  battled  against  by  some  eminent  thinkers.  The 
book  before  us  does  much  to  upset  the  arguments  of  these 
thinkers  and  to  support  the  theory  they  denounce.  But  there 
is  a  middle  position  for  those  who  neither  agree  with  the  theory 
of  a  separate  creation  for  every  genus  nor  with  the  develop- 
ment of  animal  life  from  one  germ  form.  This  position  may 
be  described  in  the  words  of  Tennyson  as  a  '  sunless  gulf  of 
doubt.'  Doubt,  however,  is  not  always  sunless;  and  besides 
to  admit  a  doubt  is  at  least  frank,  and  we  prefer  it  to  being 
dogmatic.  Still  even  believers  in  a  separate  creation  for  every 
genus  cannot  but  admit  that,  notwithstanding  the  great 
diversity  in  the  animal  kingdom,  there  is  a  oneness  of  princi- 
ple, a  common  style  of  architecture,  so  to  speak,  pervading  all 
animal  life,  which  we  see  in  the  structure  of  teeth,  arms,  legs, 
wings,  &c. 

"The  construction  of  a  horse's  teeth  points  to  the  inevitable 
conclusion  that  he  is  a  vegetarian,  but  the  various  changes  in 
the  dentition  of  a  long  line  of  fossil  horses  indicate  that  he  was 
once  probably  carnivorous,  or  perhaps  omnivorous.  Teeth, 
like  other  parts  of  the  body,  are  influenced  by  use  ;  the  change 
is  not  so  obvious,  but  it  is  no  less  certain.     As  the  volume 


THE    WEDGE    OF    EVOLUTIOX.  271 

before  us  affirms,  for  example,  tlie  canine  and  remnant  teeth 
have  been  much  reduced  in  size,  and,  if  Mr.  Darwin's  theory 
is  correct,  are  probably  in  the  course  of  ulriraate  extinction. 
Now,  the  function  of  a  canine  tooth  is  to  tear,  not  grind.  If 
animals  that  now  use  their  canines  for  teaiing  flesh  were  com- 
pelled to  subsist  on  vegetable  food,  there  would  perhaps  be  no 
marked  change  in  a  generation,  but  there  certainly  would  be 
in  a  series  of  generations.  We  therefore  conclude  that  horse 
dentures  have  adapted  themselves  to  a  gradual  but  great  change 
in  the  animal's  mode  of  existence,  a  gradual  departure  from 
the  original  custom  of  subsisting  on  food  which  demanded 
tearing  teeth,  and  that  it  took  to  vegetarianism  naturally. 
Fossil  remains  would  force  this  conclusion  on  us,  however 
much  we  might  desire  to  doubt  it.  But  why  should  we  have 
such  a  desire  ?  To  admit  development,  say  some,  is  but  the 
thin  end  of  the  wedge  of  Evolution.  Be  it  so.  It  is  the  func- 
tion of  scientific  wedges  to  split  old  and  false  notions,  and  vi^ho 
ever  heard  of  a  man  putting  the  thick  end  of  a  w^edge  in  first? 
Whether  development  is  the  thin  end  of  the  wedge  of  Evolu- 
tion or  not  we  do  not  care  much  to  inquire.  If  a  man  studies 
horses' teeth  of  to-day  as  well  as  those  of  human  boings,  he 
will  come  to  the  conclusion  that  in  both  there  are  signs  of  great 
development  when  compared  wnth  the  teath  of  thousands  of 
years  ago.  Ho  will  observe  not  change  merely,  but  signs  of  a 
higher  order  of  being— signs  of  an  evolution  of  the  superior 
from  the  inferior. 

''To  some  people  Evolution  is  a  bugbear,  and  the  idea  that 
human  beings  are  capable  of  physical  development  is  not  much 
less.  We  advise  such  people  not  to  read  Mr.  Clarke's  book.  It 
would  trouble  them.  They  might  cast  it  into  the  fire  and  thus 
waste  their  money.  But  intelligent  seekers  after  truth,  those 
who  find  the  '  gulf  of  doubt '  in  which  they  are  floundering 
too  sunbss  for  their  light-loving  souls  ;  those  who  are  not 
afraid  to  meet  the  doctrines  of  scientific  men  face  to  face,  may 
read  this  work  with  profit.  Without  desiring  to  disparage  its 
author,  we  may  say  that  its  chief  value  lies  in  the  fact  that  it 
is  composed  largely  of  selections  from  the  works  of  men  of 
special  knowledge  on  the  subject  of  the  treatise  and  of  various 
germain  subjects.  Much  credit  is  due  to  him  for  collecting  m 
so  compact  a  form  such  a  large  quantity  of  valuable  matter, 


272  APPENDIX. 

which  was  scattered  over  cyclopedias,   translations  of  learned 
secieties,  and  other  costly  books." 

Mr.  Tuttle,  in  a  letter  to  me  (a  few  words  of  which  have 
been  interpolated  in  the  foregoing  article),  in  substance  says  : 

"  At  the  close  of  the  Eocene  period  there  were  three  distinct 
types  of  animals  descended  from  a  common  ancestor  that  are 
now  represented  by  the  horse,  tapir,  and  rhinoceros.*  Let  us 
suppose  that  a  pair  of  animals  gave  birth  to  the  offspring  which 
were  to  be  the  parents  of  these  three  types.  What  would  be 
the  process  of  development?  These  animals,  with  their  mates, 
by  some  means  get  separated.  The  parent  of  the  future  tapir 
goes  one  way  ;  that  of  the  rhinoceros  stays  at  home,  while  he 
who  is  to  beget  the  horse  wanders  away  from  the  marshes  and 
rivers  to  the  dryer  laud.  Circumstances  over  which  he  has  no 
adequate  control  place  him  where  alligators,  crocodiles,  and 
other  animals  that  he  has  been  accustomed  to  attack  with  his 
tushes  are  absent.  His  feet,  which  are  many-toed,  broad,  and 
adapted  to  walking  in  the  mud,  now  tread  hard  soil  ;  his  canine 
teeth,  which  were  used  in  tearhig  fl  sh.  now  find  little  employ- 
ment ;  his  neck,  from  constant  stretching  r.s  he  crops  the  foliage 
of  the  bushes,  lengthens  ;  a  more  rapid  gait  is  acquired  by  a 
gradual  contraction  of  the  toes  and  the  lengthening  of  the  legs, 
and  eventually  this  modified  animal  becomes  a  horse.  Tiius  is 
told  in  a  few  words  wliat  1  believe  has  1  ecu  g(  ing  on  in  the 
course  of  hundreds  of  thousands,  perhaps  millions  (f  years." 

It  is  noteworthy  that  a  young  man  like  Mr.  Tuttle  should 
entertain  views  similar  to  those  of  such  on  experienced  evolu- 
tionist as  Prof.  Cope.  It  is  not  difficult  to  believe  that  the 
bear-like  Amblypoda,  which  Prof.  Ccpc  thinks  were  tlio  com- 
mon  -progenitors  of  the  horse,  tapir,  rhinoc-rcs,  elephant,  Szc, 
were  carnivorous,  and  there  certainly  is  some  rnalogy  between 
the  sapposiliiious  animal  just  described  by  Mr.  Tutile  and  the 
Amblypoda.  Change  of  food  was  probably  as*  instrumental  in 
prorlucing  the  great  physical  changes  in  early  fossil  animals  as 
change  of  habitat  and  climate.     And  change  of  food  does  not 

*  Compare  with  quotation  from  Prof.  Huxley  in  third  note,  pp.  65-66; 
alt-o  with  same  from  Prof.  Owen,  pp.  106-7. 


FOOD  A  FACTOR  IN  EVOLUTIOX  PROBLEM.   ;^T3 

necessarily  entail  extinction,  unl-ss  it  be  food  directly  opposed 
to  the  animal's  nature  ;  and  it  roatters  not  if  the  change  is 
compulsory,  for  cliauges  of  taste  may  be  either  natural  or  cul- 
tivated. For  example,  children  relish  food  they  cannot  eat 
when  adult,  and  vice  versa,  which  is  natural  ;  and  an  appetite 
for  sam3  foods  may  be  cultivated  at  any  age.  Again,  food 
probably  causes  much  of  the  change  in  tame  boars  and  other 
animals  that  become  wild,  and  vice  versa.  Still  it  is  not  strictly 
correct  to  say  that  the  horse  as  such  was  ever  carnivorous,  for 
an  animal  that  was  the  common  ancestor  of  so  many  diverse 
animals  was  as  much  one  as  the  other. 

In  1878,  in  a  hastily  written  prospectus  of  a  work  that  Dr. 
C  D.  House  designed  to  publish,  in  conformity  with  his 
(House's)  views,  I  said  the  horse  was  probably  once  carnivor- 
ous. Thinking  Dr.  House  to  be  mistaken,  I  wrote  to  Dr.  Leidy 
of  Philadelphia,  asking  his  opinion  on  the  subject.  He  agreed 
with  me. 


THE   ORIGINAL   HOME   OF   THE   HORSE. 

There  is  no  doubt  that  the  original  home  of  the  horse  is  not 
Europe,  but  Central  Asia;  for  since  the  horse  in  its  natural 
state  depends  on  grass  for  its  nourishment  and  fleetness  for  its 
weapon  (safety),  it  could  not  in  the  beginning  have  thriven 
and  multiplied  in  the  thick  forest-grown  territory  of  Europe. 
Much  rather  should  its  place  of  propagation  be  sought  in  those 
steppes  where  it  still  roams  about  in  a  wild  state.  Here  too 
arose  th3  first  nations  of  riders  of  which  we  have  historic 
knowledge,  the  Mongolians  and  the  Turks,  whose  existence, 
even  at  this  day,  is  as  it  were  combined  with  that  of  the  horsj. 
From  these  regions  the  horse  spread  in  all  directions,  especially 
into  the  steppes  of  Southern  and  Southeastern  Russia  and  into 
Thrace,  until  it  finally  found  entrance  into  the  other  parts  oi 
Europe,  but  not  until  after  the  immigration  of  the  people. 
This  assumption  is  at  least  strongly  favored  by  the  fact  that 
the  further  a  district  of  Europe  is  from  those  Asiatic  steppes, 
i.e.,  from  the  original  home  of  the  horse,  the  later  does  the 
tamed  horse  se2m  to  have  made  its  historic  appearance  in  it. 
The  supposition  is  further  confirmed  by  the  fact  that  horse- 


27-L  APPE^*DIX. 

raising  among  almost  every  tribe  appears  as  an  art  derived 
from  neighboring  tribes  in  the  East  or  Northeast.  Even  in 
Homer  the  ox  appears  exclusively  as  the  draught-animal  in 
land  operations  at  home  and  in  the  field,  while  the  horse  was 
used  for  purposes  of  war  only.  Its  employment  in  military 
operations  was  determined  by  swiftness  aloae.  Ttiat  the  value 
of  thi;  horse  must  originally  have  depended  on  its  fieetness, 
can  easily  be  inferred  from  the  name  that  is  repeated  in  all  the 
branches  of  the  Indo-European  language,  and  signifies  nearly 
"hastening,"  "quick."  T lie  same  fact  is  exemplified  by  the 
descriptions  of  the  oldest  poets,  who,  next  to  its  courage,  speak 
most  of  its  swiftness  --J'/i^?  Popular  Science  Monthly  for  June, 
1882. 


ELEPHANT   TOOTH-GERMS. 

MM.  PouczET  AND  Chabrit  ( Lc  Progres  Medical),  having 
examined  the  germs  of  the  teeth  of  a  fetus  of  an  elephant  in 
the  Jrtrdin  des  Plantes,  have  concluded  that  the  general  opin- 
ions on  this  subject  are  not  exact.  Since  the  works  of  Robin 
and  Kolliker,  it  has  beau  assumed  that  there  is  produced  on 
the  surface  of  the  gum  a  primary  epithelial  bud  (b-ourgeon),  that 
Pouchet  calls  the  epithelial  plate  and  Kolliker  the  adamantine 
organ  or  enamel,  which  sends  out  a  prolongation  destined  to 
form  a  temporary  tooth,  and  afterward  a  second  prolongation 
for  a  permanent  tooth.  The  more  recent  experiments  seem  to 
prove  that  the  permanent  teeth  are  not  given  forth  from  the 
neck  of  the  temporary,  and  that  there  is  no  secondary  adaman- 
tine organ.  In  the  elephant,  where  there  is  no  second  set  of 
teeth,  the  same  plate  or  layer  appears,  together  with  the  same 
prolongations.  The  two  faces  of  the  epithelial  prolongation 
do  notliave  the  same  structure  ;  the  inner  face  is  composed  of 
cylindrical  cells,  while  in  the  outer  face  there  is  a  mingling  of 
epithelial  and  tissue  cells.-iV.  Y.  Med.  Times,  Feb.  1881  (trans- 
lated  by  Dr.  T.  M.  Strong). 

The  deductions  of  MM.  Pouchet  and  Chabrit  may  be  correct 
in  principle,  but  it  is  a  mistake  to  say  the  elephant  has  only 
one  set  of  teeth,  for  he  has  six  or  more,  and  may  in  fact  be  said 


THE   ELEPHANT   TEETHIXG    ALL   THE   TIME.        275 

to  be  always  teetliing.     The  following  facts  are  parLly  based 
on  Cuvier,  Owen,  and  Wm.  Jacobs: 

Tlie  grinders,  wliicli  are  constantly  in  progress  of  destruction 
and  formation,  are  not  deciduous  in  tbe  ordinary  sense,  for  tbey 
succeed  eacb  other  horizontally  instead  of  vertically,  and  not 
more  than  one  wholly  or  two  partially  (one  on  each  side  in  each 
jaw)  is  in  use  at  one  time.     As  the  fore  part  of  the  tooth  in  use 
is  worn  away  by  attrition  and  its  roots  diminished  by  absorp- 
tion, its  successor  pushes  it  forward  (a  movement  that  appears 
to  be  facilitated  by  the  direct  backward  and  forward  action  of 
the  lower  jaw),  and  a  large  part  of  the  replacing  tooth  is  in 
use  for  some  time  before  the  first  is  entirely  shed.     Thus  a 
grinding  surface  is  ready  all  the  time.     The  milk  teeth  are  cut 
eight  or  ten  days  after  birth,  the  upper  preceding  the  lower, 
and  it  is  about  two  years  before  they  are  entirely  displaced  by 
tha  second  set.     The  second  set  is  in  use,  but  gradually  dis- 
appoarina-,  from  the  second  year  to  the  sixth,  when  the  third  is 
fully  in  i)osition  ;  it  in  turn  serves  till  the  ninth  year,  when 
the  fourth  set  is  in  position  ;   and  thus  it  continues  to  the  end 
of  tlie  animal's  life-103  or  even  150  years.     Each  succeeding 
tooth  requires  at  least  a  year  more  than  its  predecessor  to  be 
completed. 

The  grinders  are  remarkable  for  their  size  and  the  complexity 
of  their  structure,  the  upper  and  louver  teeth  being  much  alike. 
They  are  composed  of  ivory  (dentine),  enamel,  and  a  large 
quantitv  of  cement.  The  crown  is  short  in  proportion  to  the 
depth  Jf  the  base  or  root,  only  a  small  part  appearing  above 
the  o-um.  In  the  Asiatic  species  the  crown  is  composed  ot 
trans"xrse,  vertical,  enamel-plated  dentine  ridges,  about  half 
an  inch  apart,  and  joined  together  by  cement.  Tiie  ridges  are 
nearly  strai-ht  and  are  tooth-like  in  appearance.  The  ndges 
are  good  indicators  of  age,  the  first  set  of  teeth  having  4,  the 
second  8  or  9.  the  third  12  or  13,  the  fourth  15,  and  so  on  to 
the  seventh  or  eighth,  which  have  23  or  23.  In  the  African 
species  the  crown  is  studded  by  lozenge- shaped  projections  in- 
stead of  ridcres.  A  tooth  of  the  elephant  Colambiis,  an  excellent 
specimen,  which  may  be  seen  in  Worth's  Museum  (New  York) 
weighs  12  pounds  ;  its  breadth  is  7  inches  (the  aggregate  of 
the  siY  back  teeth  of  the  horse) ;  thickness,  2^  ;   length,  11. 


276  APPENDIX. 

It  lias  only  13  crown  ridges,  and  is  therefore  little  above  a 
medium -sized  tooth."-^  The  crown  resembles  a  small  Belgian 
paving  stone,  while  the  taper  of  the  root  resembles  that  of  a 
heart. 

The  elephant  is  a  vegetarian,  and  the  construction  of  its 
grinders  is  a  striking  example  of  the  adaptation  of  the  teeth  of 
an  animal  to  its  food. 

Tiie  tnsks,  two  in  number  and  belonging  to  the  upper  jaw, 
are  shed  but  once.  The  deciduous  tusks  cut  between  the  fifth 
and  seventh  months  and  are  shed  about  the  end  of  the  first 
year,  their  roots  being  considerably  absorbed.  They  rarely 
exceed  3  inches  in  length  and  ^  of  an  inch  in  diameter.  About 
two  months  after  the  shedding  of  the  temporary  tusks,  the 
permanent,  which  are  situated  to  the  inner  side  of  and  behind 
the  former,  emerge  and  continue  to  grow  throughout  life.  They 
have  an  enamel  coat,  but  are  mostly  composed  of  ivory  ,  a 
remarkably  fine  and  elastic  form  of  dentine  (differing  somewhat 
from  the  dentine  of  other  teeth),  and  are  hollow  for  a  consider- 
able part  of  their  length.  Thej  are  deeply  imbedded  in  the 
skull.  Sir  Samu2l  Baker  found  one  8  feet  long  with  22  inches 
girth  to  be  imbedded  31  inches. 

The  tusks,  which  are  formidable  defensive  and  offensive 
weapons,  and  which  correspond  to  the  canine  teeth  of  other 
animals,  vary  much  in  length,  weight,  and  curvature.  Gordon 
Gumming  found  a  tusk  in  Africa  that  measured  10|  feet  and 
weighed  173  pounds.  The  average,  however,  is  not  over  7  feet 
and  103  pounds.  They  are  generally  smaller  in  the  female 
than  in  the  male,  but  accordin2:  to  Cuvier  the  African  species 
are  the  same  in  this  respect.  In  the  Indian  elephant  some  have 
a  pronounced  upward  curve,  some  are  nearly  straight,  while 
others  resemble  the  letter  S.  They  are  sometimes  used, as 
levers  in  uprooting  mimosa  trees  whose  crown  of  foliage  is 
beyond  the  reach  of  the  trunk.  In  Ceylon,  where  the  elei)harit 
lives  chiefly  on  grass  and  herbage,  the  tusks  are  generally 
absent  in  both  sexes.  The  bullets  sometimes  found  in  the 
ivory  are  probably  first  lodged  in  the  pulp  cavity  and  then 
carried  to  the  solid  part  by  growth. 

*  Mr.  L.  G.  Yate«  of  CentCM-ville,  California,  says  fossil  elephant  molars 
weighing  25  pounds  have  been  discovered  in  that  State. 


HUM  AX   iHUMAXE)   DENTISTRY.  217 

A  large  elephant  weighs  7,000  pounds.  The  Indian  elephant 
is  10  feet  in  hight,  the  African  12  ;  a  skeleton  in  the  St.  Peters- 
burg Museum  is  16|. 


HUMAN    TEETH. 

FILLING  children's  TEETH.* 

Filling  the  deciduous  or  first  set  of  teeth  prevents  decay 
and  consequent  injury  to  the  second  set,f  alleviates  pain,  facil- 
itates speech.^  mastication,  and  regularity  in  the  growth  of  the 
second  set,  aids  in  keeping  the  breath  pure,  and  is  conducive 
to  health  at  a  very  critical  time  of  life.  They  should  be  filled 
as  long  as  filling  will  preserve  their  usefulness,  and  at  all  times, 
for  some  are  shed  as  early  as  the  fifth  or  sixth  year,  others 
as  late  as  the  eleventh  or  twelfth.  Any  of  the  usual  fillings 
will  answer,  the  sole  object  being  to  arrest  decay  and  "aid 
somatic  development "  (Odell).  Children  should  be  taught  to 
use  a  brush  and  proper  dentifrices.  Defective  teeth  are  often 
the  result  of  improper  diet  during  utro-gestation.  Drs.  J.  Allen 
and  G.  M.  Eddy  say  that  mothers  do  not  eat  enough  bone- 
producing  food,  such  as  oatmeal,  bread  made  from  unbolted 
flour,  &c.,  but  admit  that  such  foods  do  not  assimilate  in  every 
case.  Dentists  differ  as  to  the  advisability  of  the  use  of 
anaesthetics  in  treating  children. 

The  teething  period  is  longer  than  is  usually  supposed.  It 
begins  about  the  seventh  month  before  birth  §  and  continues 

*  The  object  of  this  brief  article  is  merely  to  call  attention  to  an  impor- 
tant subject.  My  own  attention  was  directed  to  it  by  Mr.  E.  A.  Rockwell 
in  an  interesting  article  in  the  New  TorTc  Sun.  Readers  who  wish  to  study 
the  subject  are  referred  to  the  elaborate  works  of  dentists.  Besides  the 
dentists  mentioned  above  I  have  consulted  Drs.  G.  H.  Rich,  F.  Abbott,  and 
C.  E.  and  J.  S.  Latimer,  all  of  "NTew  York. 

t  Dr.  T.  P.  Wagoner  (Knightstown,  Ind.,  Dental  ISfeivs)  approves  the 
above,  and  in  addition  says  the  development  of  a  permanent  tooth  may 
be  retarded  by  a  dead  deciduous  tooth. 

X  Haller  and  other  physiologists  give  minute  accounts  of  the  effects 
produced  by  teeth  in  articulating  the  various  letters  of  the  alphabet.— 
Bostock. 

§  For  the  development  of  human  tooth-germs  from  the  seventh  week 
tUl  birth  see  page  46. 


r^rs 


APPENDIX. 


till  the  age  of  1 


i  or 


years.     The  annexed  cut  (Farrar)  repre- 


sents (above  the  dotted  line)  an  upper  deciduous  set  of  teeth. 

1,  1,  central  incisors,  erupt  between  the  5tli  and  6th  mouths: 

2,  2,  lateral  incisors,  7th  and  lOih  months  ;  3,  3,  canines  (eye 

teeth),  12  th  and 
16th  months  ;  4,  4, 
5,5,  all  molars,  14th 
and  86th  months. 
Total,  20.  The  low- 
er teeth  usually 
precede  the  upper 

.  by  a  few  weeks. 
6,  6  do  not  belong 
to  the  deciduous 
set,  but,  as  they 
erupt  between  the 
fifth  and  sixth 
years,  are  usually  classed  with  them,  and  frequently  decay 
beyond  remedy  before  the  mistake  is  discovered. 

Dr.  J.  N.  Farrar  (New  York),  to  whose  works  I  am  indebted 
for  information,  says  {Missouri  I>e?ital  Journal,  April,  1880): 
"  The  statistics  in  this  country  show  that  out  of  about  80  peo- 
ple of  all  classes  only  one  has  sound  teeth.  This  is  the  result 
of  a  combination  of  causes — systemic  disturbances  from  climate, 
food,  crossing  of  races  and  types,  and  neglect.  Most  of  the 
cavities  are  caused  by  anatomical  imperfections  or  overcrowd- 
ing, nearly  all  of  which  develop  before  the  thirty-fifth  year. 
*  "  *  The  science  of  dentistry,  however,  has  checked  much 
of  this  suffering,  and  at  this  time  (1879)  there  are  12,000  dentists 
annually  }:»acking  into  tooth-cavities  about  half  a  ton  of  gold — 
$500,000.  The  estimated  gold  coinage  value  in  this  country  is 
about  $150,000,000;  this  sum,  at  the  rate  gold  is  used  for  fill- 
ings, would  be  transferred  to  graveyards  in  300  years.  The 
value  of  the  cheap  fillings  is  about  $100,000,  and  there  are 
annually  manufactured  about  3,000,000  artificial  (porcelain) 
teeth.  *  *  "  If  $100  is  put  on  interest  (7  per  cent.)  at  the 
birth  of  a  child,  it  ought  to  pay  all  dontal  expenses  till  the  age 
of  30  years ;  but  if  the  child's  teeth  are  neglected,  increased 
dental  bills  result,  with  poor  teeth  at  best.  The  only  question 
remaining  is,  is  the  baby  worth  $100  ?  " 


INDEX. 


Abnormal  Dentition,  human,  128 ; 
horse,  142. 

Abnormal  Teeth,  115-123. 

Abnormal  Tooth,  dcBcription  of,  123. 

Absorption  of  roots  of  foals'  teeth, 
48,  70-1 ;  do.  eiephant,  275-6  ;  den- 
tal journal  on,  288. 

Alfort  Veterinary  College,  U\  142. 

Amblypod:i,  the,  257 ;  description 
of,  261-2. 

Americis,  the,  richness  of  fossil  re- 
mains in,  lOj-113. 

Anacodon,  fossil  horse,  263. 

.\nchippus,  fossil  horse,  93. 

Anchitheriuin,  fossil  horse,  96,  111. 

Anchitheriiimaureliauenje,  teeth  of, 
23(5-7  ;  toes  of,  285. 

Animal  Kingdom,  divfirslty  yet  oue- 
ness  of  principle  in,  270. 

Animil,  a  snpposititions,  272. 

Anoplotliert?,  tcth  of,  65. 

Antelope  montana,  tushes  of.  78. 

Apparatus  dental,  exuberance  of 
particular  parts  of,  141-3. 

Appeadix.  fossil  horses,  evolution, 
original  home  of  horse,  elephant 
and  children's  teeth,  257  -27*'. 

Apsyrtus,  advice  of,  116. 

Arcades  (of  teeth)  anomalies  in  form 
of,  110,  141. 

Aristotle,  mistake  of,  69. 

Arloing,  M.,  resection  of  nerves,  217. 

Armaiillo,  the,  229. 

Artiodactyla  (ho^^s,  &c.).  257,  262. 

Ass,  experiment  on  an,  217,  318. 

Babingtox,  B.,  242. 

Bacon.  Francis,  theory  of,  15. 
Baer,  Von,  comparisohs  by.  81, 
Bake;-,  S.,  report  of,  181,  189. 
Batrachla,  the,  229,  230. 
Bay,  Surgeon,  discovery  of,  117. 
Bell,  C,  discoveries  of,  217,  218. 
Bell.  Thoma-i,  theories  of,  26-7, 83^. 
Berger-Perriere,  discovery  of,  116. 
Berzelius,  discoveries  of,  15. 


Birds,  fossil,  teeth  of,  114. 

'  Bishopiug,''  modus  operandi  of.  211. 

Black,  Surgeon,  expermient  of,  29. 

Blaine,  Surgeon,  fractured  jaw,  197. 

Blastema,  nature  and  color  of,  34-5. 

BluQienbach,  on  ciuudrnmana,  251. 

Boar,  the  marked,  grinders  of,  10. 

Bo:ir,  wild,  tame,  changes  in,  84, 273. 

BjII,  Dr.,  tooth  pulp.  31. 

Bojaiuis,  disc. .very  of,  53, 

Bond's  •  Dental  Medicine,'  extract 
from,  123,  129. 

Boulcy,  M.  H,,  development  of  teeth, 
45  ;  gi'inders,  62  ;  formation  of 
enamel,  64;  growth  of  teeth  dur- 
ing life,  73  ;  diseases  of  teeth,  i;::8  ; 
diseases  and  dentistry  of  teeth,  1.39- 
162;  swallowing  teeth,  192,  193  •, 
removal  of  fractured  jaw,  197,  198, 

Bourgelat,  Prof.,  milk  molars,  69. 

Brandt,  L..  length  of  incisors,  74  ; 
age  of  Spanish  horses,  crib-biters 
and  mules,  215 ;  age  by  shape  of 
teeth,  215. 

Brewster.  B.  S  ,  letter  from,  292. 

Broadhead,  G.  C,  account  of  fossil 
tooth,  112,  113. 

Broderip,  Mr.,  a  whale's  tooth,  79. 

Burns,  John,  description  by,  239. 

Butterfly,  the,  transformations  of,  81. 

Cachalot,  the.  79. 

Calcigerons,  origin  of  word,  18. 

Cattle,  teething  period  of,  91,  92. 

Came],  the,  teeth  of,  66. 

Camper,  P.,  temporary  canines,  52. 

Canines,  lemporarv,  51,  52. 

Calculus  Concretions,  192.  193.  230. 

Caries,  cause  of,  144-154;  165-173? 
svniptoms  of.  1-18-15-1 ;  different  In 
different  teeth,  151  ;  odor  of,  153,' 
treatment  of.  155-171  ;  treatment 
after  treohming  sinuses  for,  170  ; 
other  dental  cases,  177-193  ;  con- 
founded with  glanders,  176,  18J, 
185  ;  definition  of,  231. 


280 


IXDEX. 


Cartwriglit,  W.  A.,  report  of,  193  ; 
11  actiue  of  jawbone,  19li. 

Cauca.-iaii  Euce^s  teeth  of,  99. 

Cement,  the,  9  ;  size  of  tubes  of,  16; 
use  of,  17  ;  mistaken  for  tartar,  17  ; 
vascularity  of.  17  ;  tiiiuuess  of,  17  ; 
color  of,  18  ;  resemblance  to  bone, 
23;  germs  of,  43;  a  proiectinj^ 
varnioh,  59,  GJ;  microscopical  char- 
acter of,  133. 

Chabrit,  M.,  tooth-germs,  274. 

CiialicoiheriidiB  (fossil  horses).  260. 

Chandler,  C.  F.,  on  albumen,  227. 

ClTauveau,  A.,  harmony  of  teeth  with 
general  system,  11 ;  development 
of  tooth-germs,  41,  42  ;  description 
of  incisors,  58.  5=),  60  ;  growth  of 
teeth  during  life,  73. 

Cherry,  \V.  A.,  shedding  teeth,  53-1  ; 
judging  ag;;  by  shape  of  teeth,  2C4. 

Cbevrotain,^78  ;  description  of,  232. 

Clay  worth,  Siirg.,  report  of,  197. 

C  pieman.  Surgeon,  di-^covery  of,  116. 

'  Columbus  '  (elephant),  tooth  of,  275. 

Coluber  Scaber  (serpent).  121. 

Comparalive  Anatomy,  233. 

Conrad,  T.,  discovery  of,  113. 

Complex  grinders,  cause  of.  268. 

Concomitant  Variation,  a  factor  in 
evolution  problem.  98. 

Condylarthra,  the,  2W-1,  264. 

Cope,  E.  D.,  editor  American  Natur- 
alist, 113;  physiological  homolo- 
gies, 233;  discovers  Phenacodus 
(teeth)  and  other  fossil  horses, 
259->;9  ;  opinion  of  the  Amblypo- 
da,  261-2. 

Copybara,  the,  criudcrs  of,  10;  de- 
scription of,  233. 

Coucrhing  and  Teething,  treatment 
for,  92. 

Crib-biting,  effect  of  on  teeth,  212- 
13 

Camming,  G.,  elephant  tusk,  276. 

Cuvier,  F  ,  16  ;  note  on,  6j  ;  bones 
and  teeth  of  recent  and  fossil 
horses,  106;  ojjhthalmic  ganTlion, 
221 ;  elephant  teeth,  275. 

Dana,  Prof.,  geology.  240. 

Dandiiii,  J,,  silver  and  golden  hued 
teeth,  25-6. 

D'Arboval,  teething.  87. 

Darwin,  C.  R.,  tnshe;  of  various  ani- 
mals, 77,  78.  79  ;  changes  in  human 
teerh,  99. 

Dawson,  J.  W.,  geology,  240;  mio- 
cene  period,  2'M ;  pliocene  period, 
250. 

Diy,  E.  C.  H.,  narwhal.  246. 

Deciduous  teeth,  retention  of,  129. 

Delafond,  M.,  on  trephining.  101. 

Denenbonrg,  F.,  report  of,"l23. 

Dental  Cysts,  importance  of  study 
of,  115;  microscopical  character  of 


teeth  in,  118  ;  reports  and  theories 

on,  115-126. 
Dental  Canal,  the,  31,  224,  284. 
Dental  i^'vsts,  115-l^b. 
Dental  Nerve,  the,  224-226. 
Dentinal,  origin  and  use  of  word,  8. 
Dentinal  Pulp,   network  of  looped 

capillaries  of  the,  33-4. 
Deaiiual  Star,  59 ;    description  of, 

209. 
Dentinal  Tubes,  office  and  color  of 

22,  23 ;   their  two  curvatures,  23 

dichotomously  brauched,  131,  133 

diameter  of,  132  ;  length  of  curves, 

133. 
Dentine,  the,  S,  14. 
Dentine  Germ,  43,  59. 
Dentition  Fever,  93. 
Dentition,  permanent,  53-74. 
Di^utitiou,  temporary,  47-52. 
Denlition,  third,  cases  of,  128. 
Digital  reduction,  cause  of,  269. 
Dinoceras   mirabilis  (fossil),    horns 

and  canine  teeth  of,  236. 
Diverticula,  use  of,  22,  235. 
Dog  tooth-germs,  grafting  of,  27-8. 
Draper,  J.  W.,  obligation  to,  4. 
Dugong,  the,  79 ;  description  of,  235. 
Dunglison,  E.,  development  of  leoth, 

45  ;  diseases  of  teeth,  1.37  ;  calculi, 

193 ;  vocabulary,  227-256. 

Eddy,  Dr.,  children's  teeth.  277. 
E  iinburgh  Veterinary  College,   re- 
port of,  179,  180. 
Editor  Veterinarian,   comments  of, 

184;  report  of,  201,202. 
Elasmothere,  the,  great  size  of,  107; 

enamel  festoons  of  molars  of,  107  ; 

coMnecting  link  between  horse  and 

rhinoceros,  107. 
Elephant,  great  quantity  of  cement 

in  grinders  of,   10 ;   unique  mode 

of  cutting  and  shedding    several 

dentitions;    size,    structure,   &c., 

274-7;  affinities  with  rodents,  260. 
Embryo,  human,  transformations  of, 

81-2  ;  definition  of,  2;36. 
Embryology,  80-82. 
Enamel,    the,   10;   lubes  of,  18,  19; 

color  of,  19;  membranous  sheaths 

of,  59;  plications  of,  106. 
Enamel,  the  two  rings  of,  59. 
Enamel-Fibers,    direction    of,    20; 

curves  of,  20;  form  and  size  of,  20; 

diameter  of,  134. 
Eocene  (period)  fossils  of,  236. 
Equi'l-ie,  the,  tooth  rf,  261. 
Evolution,  doctrine  of  77-9.  98-0.237; 

257-6) ;    from  inferior  to  ouperior, 

271 ;  a  buirbear,  271. 
Exostoses,  17,  116. 

Faenkel,  discovenea  of,  15. 
Falconio,  Surg.,  di-fcovery  of,  118. 


IXDEX. 


Ji81 


Ferofuson,   P.  B.,   development    of 

teetu,  45  ;  grinders.  Qi  ;  the  forma- 
tion of  enamel,  64 ;  growth  of 
teeth  dm-iug  hie,  "i^;  aiseaijes  of 
teeth,  T6S  ;  diseases  and  dentistry 
of  horses'  leeth.  Vi\i-\ij-l;  swallow- 
ing teeth,  1;)2.  193. 

Filling  children's  teeth,  277. 

Fleming,  G.,  dental  cysts,  115-139  ; 
fractnred  jaw,  195,  190 ;  on  glan- 
ders, 199. 

Food,  for  foals,  50;  for  tooth-cough, 
91  ;  for  unequal  wear  of  grinders, 
143;  after  trephining  for  caries, 
15:),  IG2 ;  for  defective  teeth,  im- 
proving skin,  fever,  convalescence, 
&c.,  KW-l;  sifting  of,  171;  changes 
caused  by,  272;  bone-producing, 
27T  ;  sugar  for  horses,  3U. 

Forthomme,  M.,  milk  canines,  52. 

Fossil,  cat-like  animal,  a,  244. 

Fossil,  definition  of,  114. 

Fossil,  hog-like  elephant,  with  tusks 
in  both  jaws.  24i. 

Fossil  Horses,  cause  of  changes  in 
teeth  of,  2G8;  do.  reduction  in 
toes  of,  269.     ^See  Horses,  fossil.) 

Fossil  Horses,  recent  discoveries  of, 
257-269. 

Fossil  Tooth,  a  diseased,  173. 

Fractured  Jaws,  194-202. 

Fungus  Hsematodes,  173  ;  definition 
of,  239. 

Gamgee,  J,,  report  of,  t20-^. 

Ganglion,  nature  of,  220-1,  2.39. 

Garengeot.  M.,  dental  key,  156. 

GeneraJi,  Piof..  dental  cysts,  116-19. 

Geoloirv.  definition  of,  240. 

Gill.  T.,  nature  of  teeth.  12  ;  dsntu? 
formula  for  horse,  101 ;  fossil  Dirds' 
teeth,  114;  teeth  from  diverticula 
(marsupials),  235;  morphologT, 
245;  quadrumana,  251,  252;  tele- 
osts,  254. 

Girard,  M.,  acre  by  mark?  and  shape, 
206-7  ;  dentinal  star,  20a 

Glanders,  resembles  caries  of  last 
grinders.  152-3 ;  odor  of,  1.53 ;  may 
be  caused  bv  caries  of  teeth  (ab- 
sorption of  pus).  160  :  sometimes 
imaginary,  176,  180,  185;  danger 
from  and  prevalence  of  19f>. 

Gomphosis  (taoth-artJeuLaii')n),  72. 

Goodbir,  Pi-of.,  on  tooth-u-erms,  125. 

Gonbaux,  Surg.,  discovery  of.  117. 

Gowing,  T.  W..  on  teeth. '171-72. 

Grire.  O.  C,  report  of,  123,  124. 

Grinders,  the  54  ;  table*  of.  6!  :  fig- 
ures formecl  bv.  6!  ;  contrasts 
between,  61,62:  their  own  v.het- 
stones.  Go;  roots  of  fS,  70:  shed- 
fling  of,  70.  71 ;  activity  of  growth 
and  undivided  base  of,  74. 

Grouille,  Mage,  dental  cysts,  116. 


Guanaco,  78  ;  description  of,  240. 
Gubernaculum  Deutis,  the,  descrin- 

tion  of,  42. 
Gums,  shrinkage  of  the,  72,  74, 172, 

181  ;  aticcted  by  turgescence,'l51  • 

nerves  of,  225. 
Guiil,  Surg.,  Ciiscuvery  of,  117. 
Gutta-peicha  as  a  filling  lor  "teeth 

and  sinuses,  164, 177;  for  children's 

teeth,  277. 

Haeckel,  E.  H.,  embrvos.  81-2. 

Harris,  Prof..  3d  dentition,  129. 

Hartshorne,  H.,  evolution,  237. 

Ilaschischat  ed  dab,  efiect  of  on 
teeth,  25. 

Haw  of  the  horse's  eye  (membrana 
nictitans),  description  of.  import- 
ance cf  and  evil  caused  by  ignor- 
art  grooms,  S44. 

Ilayden,  Er.,  discoveries  of,  £57. 

Ha\es,  B..  tooth-palp,  dentiral 
tubes,  cells  and  curves  upon 
curves,  cement,  enamel,  &c.,  22-4  ; 
diseases  of  teeth.  137. 

Heard,  J.  M..  obligation  to,  216: 
letter  fnmi,  292. 

Heath,  J.  P..  report  of,  200,  201. 

Henoccjue.  M..  motor  nerves,  217. 

Herbert,  VV.  H..  age,  214,  215. 

Hesperornis  (bird)",  teeth  of,  114. 

Hesperornis  re<?alis,  teeth  of,  114. 

Hipparion.  fos^d  horse.  95,  96.  111. 

Hippotherium,  fossil  h(;r>e,  264-7. 

Hippotherium  gracile.  268. 

Hippopotanms.  canine  teeth  of,  63. 

Histology,  dofiLition  of,  241. 

Hitchcock.  C.  H.,  on  foss-ils.  114. 

Hoeing,  C.  F.,  obligation  to,  215  ; 
letter  from,  §92. 

Hog,  canine  teeth  of,  63. 

Horsburgh,  J.,  report  of  175. 

Horse,  signification  of  word,  274. 

Horse,  the,  theory  of  introduction 
into  America,  110;  a  vegetarian, 
270;  probably  never  carnivorous, 
272-3j  once  used  for  war  only,  274. 

Horse  Dentistry,  argument  in  favor 
of,  160  ;  dental  au'd  other  journals 
on.  287-292. 

Horse,  gcneaIog\  of,  264. 

Horse,  original  i.ome  of,  273. 

Horses,  fossil,  A' acodon,  263;  .An- 
chippns,  96,  i64 ;  Anchitheriitm. 
96,  111,  il2,  2e4;  Anchitherium 
anreliauense,  2f5.  267:  Anison- 
ebtis,  263;  Chalieotheriidge.  2t0, 
264;  Eohippus,  (supposititious), 
259  ;  Fquidge,  2G1  ;  Equus  caballrs 
primigenins,  107;  Equns  eompli- 
catus,  113;  Equ«s  ewrvidens,  107; 
Equus  fossHis,  106;  Equns  plici- 
dens.  107;  Equus  primig-enius,  107; 
Hipparion,  fci-6.  111,  112;  Hippi- 
diiim,  268 ;   Hippotherium^  264-7  : 


282 


IXDEX. 


Hippotherium  gracile,  26S;  Hyo- 
.  do.ii'a,  -i'Ji ;  Hyoiiippus,  11:2 ;  Hy'ra- 
cotlumiiu,  -^66,  2U4-5;  Lambdotlie- 
riuai.  261- T;  LopuioLlou  and  Lo- 
l)hiodoudd.e,  2d6,  '^M ;  Menisco- 
tlierium,  :ioJ-4;  Meryciiippus,  11;^ ; 
Mesohippus,  !)<",  11;:^,  264;  Orotlie 
riu:u,  25.) ;  Paleosyopou?,  2Ji';  Pa- 
leotlieriidus  2'6i;  PaleopJoIherium. 
254;  Peri^jtyc'a.is,  -263;  PJiolophns, 
238-9;  Pi-otogonia,  2(5  3 ;  Protohip- 
pus,  112,  2i5i ;  Systemodon,  259-04. 
(Sse  confu^^ion  ia  nonienclature, 
pp.  25S-9 ) 

Hor-^es,  fossil,  95-93,  106-13  ;  extinc- 
tion of  ill  SouTli  America.  10^ ; 
recent  discoveries  of,  25T-2G9; 
early  progenitors  of  (Amblypoda) 
possibly  carnivorous,  272. 

Horses,  "insane."  103. 

Horses  without  cars,  103. 

House,  C.  D.,  size  of  tooth-germs, 
31 ;  on  testhing,  47-8 ;  grinders, 
62;  remnant  teeth,  103,  104;  re- 
moving a  fr.icture:l  tooth  through 
tlie  nostril,  193,  199 ;  operations 
in  Worcester,  Mass.,  199;  idle  talk 
about  glande.-s,  19 j;  another  prob- 
able mistake,  273 

Hudson,  E.  D.,  Jr.,  mucous  mem- 
brane, 215 ;  ovaries,  248. 

Huiitor,  J.,  theories  of,  21-27  ;  enam- 
el of  grinders,  G3 ;  attachment  of 
teeth,  72 ;  use  of  canines,  83 ;  su- 
pernumerary teeth,  128  ;  proving 
the  foriuation  of  new  dentine,  209. 

Hughes,  J.,  dimensions  of  teeth,  49; 
periostoum  of  teeth.  137. 

HuxL»y,  T.  n.,  tapir,  rhinoceros,  and 
horse,  65-fi:  fossil  horses,  110-11. 

Hyohippus,  fossil  horse,  112. 

Hyracotlierium,  fossil  horse,  258-G4. 

Hyrax,  teeth  of  and  affinities  with 
rhinoceros  and  elephant,  233. 

Iguanodon,  the,  molars  of,  03. 

Incisors,  the  permauc.it,  53;  length 
of,  57;  curvature?  of,  57;  Chau- 
veau's  description  of,  53-00  ;  mi- 
croscopic character  of,  130-135. 

Incisors,  temnorarv,  47-52. 

lulbrior  Maxillary  Nerve,  the,  223-24. 

Jacobs,  W.,  on  elephant.  275. 
Jaw,  discription  of  lower,  62, 
Jaw  Movements,  changes  in,  933. 
Jaws,  fractures  of  tho,\'04-2D2. 
Jaws^  hnma'i,  chau'rcs  in,  C3,  90-100. 
Jennings,  R  ,  romiant  tooth-germs 
and  remnant  teeth,  104. 

Kno-wlson,  J.  C,  bishooing,  Sll. 
Koch,  Robert,  discovery  of,  255. 
Kolliker,  Prof.  Rudolf  Albrecht.  on 
tooth-germs,  39,  40,  40,  274. 


L4.F0SSE,  Prof.,  dental  cysts,  120. 

L:imbdotherium.  fossil  horse,  254-7. 

Lampas,  cause  of,  88-91 ;  lancing 
recommended  lor,  87,  91  ;  burning 
for  disapproved, 9U-1. 

Laucelet,  tue,  comparison  to,  81. 

Lanzillotti  Buonsaiiii,  Prof.,  on  den- 
tal cysts,  115-18. 

Lecoq,  Prof.,  canine  follicles,  44 ; 
temporary  canines,  52;  descrip- 
tion of  grinders,  69-71  ;  do.  ca- 
nines, 7G-7  ;  remnant  teeth,  100. 

Leeuvveuhoek,  discoveries  of,  13. 

Legros,  C,  experiments  of,  2i'. 

Leidy,  J.,  letter  ii-oni,  101 ;  fossil 
teeth,  113;  257,  259;  opinion  of, 
273. 

Lincoln,  A.,  211. 

Lion,  the,  canine  teeth  of,  83. 

Liquor  Sanguinis,  the.  22,  242, 

Lophiodon,  teeth  of,  258,  260, 

Lubin,  R.,  discovery  of,  127, 

LyeU,  Mr.,  N.  American  fossil  tooth 
corresponding  to  S.  Amer.,  110. 

Mackops,  Surg,,  experiences  of,  117. 

Mad.ler,  effect  of  on  teeth,  24. 

Magitot,  E.,  27  ;  development  of 
tooth-germs,  human  fetus,  4G, 

Ma'pighi,  discoveries  of,  13. 

Man,  canine  teeth  of,  82,  83. 

Man,  early  progenitors  of,  80-3. 

Manteodon,  prophecy  tooth  of,  2G2. 

Mark^,  dimensions  of,  57,  53 ;  two- 
fold use  of,  204  ;  too  much  cement 
in,  209,  210. 

Marsh,  O.  C.  evolution  of  horse,  OS- 
OS  ;  no  'mark'  in  teelh  of  early 
forms,  203;  fossil  birds'  teeth, 
114  ;  description  of  mastodon  and 
megatli:>rium,  243;  the  Lophio- 
dons,  253  ;  Orohippus,  259, 

Mastodon,  the,  109,  114,  243. 

Mav  C,  report  of.  178,  1V9. 

Mayhew,  E,  the  cement,  17,  18; 
judging  age  by  teeth,  237-8. 

Mayo,  Mr.,  experiments  of,  218. 

Megatherium,  the,  teeth  of,  107, 108  ; 
description  of,  243. 

Melanian  Races,  teeth  of.  99. 

Membrana  Nicritans,-iii  early  pro- 
genitors of  man  (Darwin),  C2 ; 
nerve  for  in  horse,  222 ;  descrip- 
tion of.  214. 

Meniscotherium,  fossil  horse,  263-4. 

Merycdiippu<,  fossil  horse,  112. 

IMesohippus.  fossil  horse,  97,  112. 

Miocene  i period)  fossils  of,  :;:44. 

Miohip!)Us,  fossil  horse,  112. 

Molar-:,"  bunodont,  2G3. 

Molir-!,  seleno'iout,  203. 

Molar-I  the,  54  ;  iiudination  of,  54  ; 
description  of,  GO-71 ;  microscop- 
ical character  of,  130-35. 

Moon  Blindness,  cause  of,  105, 


IJs^DEX. 


283 


Moore,  T.,  a  mountain  herb,  25, 
Morphology,  definition  of,  245. 
Moi-Lon,  Prof.,  treatit^e  b\^,  193. 
Mules'  Teeih,  tehiag  age' by,  215. 
Miiller,  Prof.,  dif^covery  of,  14-5. 
Mudtjac-Deer.  78,  84G. 
Musk-Doer,  78,  245. 
MyloJon,  the,  108,  246. 

Nakwiial,   the,  tushes  of,  79 ;  de- 
scrip  f  ion  of,  240. 
Nature  b;irricaJiDg  disease,  139,  209. 
Newberry,  J.  S.,  zoology,  256. 
Niebuhr,  opinion  of,  25. 
Nippers,  the,  use  of  word,  47. 
Nomenclature,  confusion  in,  258-9. 

Odontoblasts,  the,  31.     • 

OJontolithos,  the.  17,  247. 

Odontornithes  (birds),  teeth  of,  114. 

Odontonecrosis,  138. 

Odontrypy,  operation  of,  138. 

Oblinger,  O.  P..  discoverv  of.  113. 

Ophthalmic  Nerve,  the,  219-22. 

Ornithorhynchus,  the,  80,  :il7. 

Operating,  rules  for,  1,>1-1G0. 

Oreste,  Surg.,  discovery  of,  118. 

Orohippus,  fossil  horse,  teeth  of,  96, 
large  tushes  of,  97;  toes  of,  97; 
size  of  animal,  112;  name  of,  259. 

Osteo-sarcoma,  case  of,  186. 

Owen,  R.,  dental  science.  8,  10,  12- 
22;  tooth-germs,  32-37;  breadth 
and  thickness,  49  ;  temporary  ca- 
nines, 51 ;  teething,  55 ;  descrip- 
tion of  grinders,  64-68 ;  teeth  of 
anoplothere.  65  ;  da.  niminauts, 
65  ;  do.  tapir.  63  ;  do.  rhinoceros, 
6  ;  do.  megatherium,  107  ;  rem- 
nant teeth,  103 ;  fossil  horses' 
teeth,  103-10.) ;  microscopical  ap- 
pearance of  horses'  tee'.h,  130-135; 
diseases  of  teeth,  137 ;  diseased 
fossil  tooth,  173,  174  ;  the  fifth 
pair  of  nerves,  225,  223;  discovers 
Hyracotherium,  253  :  teeth  of  ele- 
phant, 275  ;  tooth-vascularity,  29  ; 
probable  circulation  and  proion2:a- 
tiou  of  nerves  iu  dentinal  tubes,  30. 

Paleontology,  definition  of,  248. 

Paleosyopous,  fossil  horse,  267. 

Paleothere,  teeth  of,  G3. 

Paleotheriidae,  fossil  horses,  261. 

Parker,  Willaid,  on  caries,  281. 

Parnell,  C,  remnant  teeth,  102. 

Parrot-Mouth,  137.  1G8. 

Eatliob2;y  of  the  Teeth,  133-174. 

PercivaU,  W..  teething,  83-83;  lam- 
pa-^,  83-90  ;  diseases  of  teeth,  138, 
135:  ophthalmic  gangli'^n.  921. 

Periosteum,  elasticity  of,  75  ,74  ;  def- 
inition of,  249-5'). 

Pcriptvchns,  a  fossil  horse  with  teeth 
resembling  a  serpent's,  263, 


Perissodactyla  (odd-toed  mammals), 
257-64. 

Pessina,  Prof.,  discovery  of.  215. 

Phenacodus  (earliest  fossil  horse), 
description  of,  260-264. 

Piei'ce,  l)r.,  opinion  of,  237. 

PJasse,  M.,  mouth-screw  153. 

Pliocene  (period),  fossils  of,  250. 

PJiohippus,  fossil  horse,  size  oi,  112; 
confusion  in  name  of,  259. 

Pliolophus,  fossil  horse,  25S-9. 

Pony,  great  suflering  of  a,  201. 

Portal,  learning  of  14. 

Pouchet,  M.,  tooth-germs,  274. 

Premolar,  reasons  for  use  of  woi'd, 
53  ;  inclination  of  the,  54. 

Processes,  alveolar,  disea>es  of,  166. 

Protogonia,  fossil  horse.  263, 

ProtohipDus,  fossil  horse,  112,  264, 

Public  Ooinion,  287-92, 

Pidp,  the  tooth,  31, 

Pulpal  Cavity,  relation  of,  22. 

Purkinje,  discoveries  of,  14,  16;  cor- 
puscles of,  9  ;  cells  of,  16. 

Quadrumana,  the,  BG,  81,  251. 
C^uain,  Jonas,  fifth  nerve  and  oph- 
thalmic ganglion,  220. 

Eamset,  J. ,  skill  of,  104. 

Ra;>ux,  C.,  obligation  to,  28. 

Renault,  Robt,,  report  of,  187-92. 

Regimen,  162-164. 

Retzius,  Prof,  discoveries  and  con- 
jectures of,  16,  19.  20,  21. 

Revel.  M.,  report  of.  197. 

Reversion,  doctrine  of,  SO. 

Rhinoceros,  the,  teeth  of.  67. 

Rhinoceros,  the  woollv,  £51. 

Rich,  Dr..  children's  teeth,  277. 

Riders,  first  nations  of,  273. 

RiiiOt,  temporary  canines,  52. 

Robin,  C,  doc  tooth-germs,  27. 

Rockwell,  E.  A.,-  report  of,  277. 

Rodet,  Surgeon,  on  dental  cysts.  118. 

Roudanoosky,  M.,  on  nerves,  218. 

Rousseau,  M.,  cutting  milk  teeth,  48. 

Ruminants,  teeth  of,  65:  four  stom- 
achs of,  252. 

Ruini,  discovery  of,  69, 

Ryder,  J.  A.,  treatise  of,  268. 

Santt.  a,  H.,  report  of,  180. 
Satterthwaite,  T.  E.,  on  corpuscles, 

233-4:  on  tubercles,  255. 
Scclidothere,  remains  of.  108. 
Schaaffhau-cn.  shortened  jaws,  99. 
Schwann,  Dr.,  researches  of.  20. 
Seelve  Prof.,  correlation  forces,  234. 
Seleetion,  natural,  98. 
Selpction,  sexual,  08. 
Sewell,  W,,  rental  cysts.  123. 
Shark,  fossil,  teeth  of.  236. 
Simonds,  Prof.,  lever-forceps,  156. 
Sinuses,  valves,  osseous  plates,  &c., 


584 


rXDEX. 


of,  152;  giitta-percha  as  a  filling  for, 

177. 
Smith,  W.,  report  of,  182-184. 
(Speculum  Oris,  use  of,  149. 
Speucer  H..  evolution,  237. 
Scar,  dentinal,  59,  2o9. 
Stone,  case  of  in  horse's  jaw,  193. 
Stron^j,  Dr.,  trunslatio;j  by,  274. 
Supin-ior  Maxillary  Nerve,  the,  222. 
Sapernumerary  Teeth,  r27-13.J  ;  139. 
Surmon,  H.,  report  of,  17r. 
Swallowing  a  Diseased  Tooth,  death 

of  a  horse  from,  187  19;2. 
Swallowing  a  heatliy  tooth,  193. 
Systemodon,  fossil  horse,  259,  260^. 

Tables  of  Grinders,  the,  01. 

Teeth,  abnormal,  cases  of  beneath 
right  kidney  and  near  nglit  ear  of 
a  lamb.  11(3-17;  on  mastoid  process 
of  temporal  bone,  posterior  part  of 
sphenoid  bone  and  in  testicle,  117; 
ill  ovaries,  orbit,  palate,  tongue, 
side  of  jaw,  cheek  and  neck,  119; 
base  of  ear,  124. 

Teeth,  absorption  roots  of,  48,  70-1, 
27o-!J,  23S. 

Teeth,  carnne  (horses'),  description 
and  probable  extinction  of,  75-77. 

Teeth,  canine,  use  of  in  different  an- 
imals, 77-83 ;  made  to  tear  flesh, 
271. 

Teeth,  constant  in  the  same  type, 
and  generally  appreciably  modified 
according  to  family,  12. 

Teeth,  continuous  growth  of,  7-3, 
143 ;  extraction  on  account  of. 
178. 

Teeth,  deciduous,  retention  of,  129. 

Teeth,  elephanr,  unique  mode  of 
cuttingand  shedding  several  den- 
titions, 274-6  ;  size,  structure,  &c.. 
274-6 ;  great  quantity  cement  in.  10. 

Teeth,  elephant  (Indian),  indications 
of  age  by,  275. 

Teeth  emanating  from  osseous  sys- 
tem, 121. 

Teeth,  foals',  absorption  of  roots  of, 
non-continuous  growth  of,  scarci- 
ty of  cement  on  crowns  of,  48 ; 
crowns  worn  off  by  attrition  rath- 
er than  shed,  .50  ;  breadth  of,  49. 

Teeth,  fossil  birds',  114. 

Teeth,  fossil  elephant,  v,-eight  of,  276. 

Teeth,  f,)ssil  horses'  (see '■  Horses, 
fossil,"  p.  2Sn. 

Teeth,  fossil  horses'  (South  and  N. 
A'.nerican),  lOl-ll. 

Teeth,  goats',  gold  and  silver  hues 
produced  in,  25-6. 

Teeth,  growine.  effect  of  madder  on, 
wliite  red  and  v>diit'%  25. 

Teeth,  horses',  anomalous  condition 
of,  142, 

Teeth,  horses',  dimensions  of,  71. 


Teeth,  horses',  discovery  that  they 
indicate  age,  215. 

Teeth,  horses',  fillings  for,  164. 

Teeth,  horses',  signs  of  improve- 
ment in,  266,  271. 

Teeth,  horses'  (^Spanish),  peculiari- 
ties of,  215. 

Teeth,  horses',  temporary,  47-52 ; 
permanent.  53-74  ;  canines,  75-C3; 
remnant,  94-114:  abnormal.  115- 
127  ;  supenuimerary,  139  ;  under 
the  microscope.  130-125 ;  pathol- 
ogy of.  1:36-174  ;  dentistry  of,  175- 
193  ;  indicators  of  age,  i()3-'215. 

Teeth,  human,  changes  in,  99. 

Teeth,  in  harmony  with  general  sys- 
tem, 11. 

Teeth,  mules',  telling  ago  by  (differ- 
ing somewhat  from  horse),  215. 

Teeth,  readily  preserved  in  a  fossil 
state,  12. 

Teeth,  remnant,  94 ;  regarded  as 
phenomcnons,  94,  101 ;  line  of  de- 
scent, 94;  not  to  be  confounded 
with  i-upernumeraiy  teeth,  94; 
the  name.  94  ;  easily  lost.  99-100. 

Teeth,  rudimentary,  99 ;  why  good 
teachers.  99. 

Teeth,  t  upcrnumerarv.  127-8,  139. 

Teeth,  three  sets  of,  128. 

Teeth,  transplanting  of.  20-29. 

Teeth,  tubes  (hollow  columns)  of,  12. 

Teeth,  value  of  to  the  ai.atomist,  11. 

Teeth,  variety  and  use  of,  10,  11. 

Teeth,  various  animals',  Boar,  77, 
84;  Cachalot,  79;  Camel,  GG,  78; 
Cattle.  91-2  ;  Chevrotain,  78.  232 ; 
Coluber  Scaber,  121  ;  Copybara 
(or  Ca'.ybara),  10,  5^33;  Dinocetas 
mirabilis  (fossil)  2.3G  :  Diigons:, '19, 
235  ;  Elephant,  77.  274  ;  do.  fossil, 

244  ;  Hippopotamus.  63  :  Hog,  63  ; 
Hyrax,  2G0;  Igi  anodon,  63  ;  Lion, 
83;  Mastodon,  109,  243;  Megathe- 
rium, 107,  243 ;   Muntjac  deer,  78, 

245  ;  Musk-deer,  78,  245  ;  Isarw  hal, 
79,  246  ;  Ornithorhynchus,  gO,  247 ; 
Rhinoceros,  67 ;  Euminants,  G5, 
252  ;  Shark  (fossil),  236 ;  Tapir, 
65;  Toxodon,  1G9,  254;  Walrus, 
77  ;  Zebra,  52. 

Teeth,  vascularity  of,  22-30;  nerves 
and  circulating  vessels  of,  26. 

Teeth,  wolf,  why  called  remnant,  94. 

Tenon,  verifies  Ruini's  discovery,  G9. 

Tennyson's  "  gulf  of  doubt,"  i70. 

Toes,  97, 112, 265 ;  cause  of  reduction 
in  number,  260  ;  form  a  semicircle 
when  aiiplied  to  the  gi-ound,  ^G9.. 

Tomes,  C.  S.,  tooth-germs,  37-41 ; 
temporary  canines,  .52 ;  dentine, 
enamel,  and  cement.  63;  attach- 
ment of  teefn,  72 ;  tushes  (f  bears, 
84-5 .  evolution,  98-9 :  no  •  mark ' 
in  teeth  of  early  fossil  horses,  203. 


INDEX. 


285 


Tomes,  J.,  a  tooth  barricading  dis- 
ease, 189. 

Tooth,  abnormal,  description  of,  123. 

TooJi,  a  diseased  lossii,  lVd-4. 

'loom,  a  fractured,  19S-y. 

TuoLh,  a  propnecy,  ^0:4. 

TootLi,  a  whale's,  description  of,  79. 

TooUi,  eiepnaut,  in  W  orih's  Museum 
(New  York),  215. 

Tooih  in  upper  jaw  of  a  bull,  127. 

Tootn,  uaiiu'e  of,  7,  8 ;  indeacence 
of.  12,  10;  no  inherent  power  of 
reparation  in,  137. 

Tooth  Fulp.  description  of,  31. 

Tooth,  rciiiuaut,  vicious  inclination 
cf  a,  134. 

Tooth,  swallowing  a  diseased  (fatal), 
18r-lJ2. 

Tooth,  swallowing  a  healthy,  193. 

Tooth-Cough,  treatment  for,  92. 

Tooth-Germs,  development  of,  31-46. 

Tootli-Ger^i<,  (.o.;s'.  grafting  whole 
germs,  separale  enamel  organs, 
dentins  caps,  &c.,  ia  dogs  and 
guinea-pigs,  those  in  the  latter 
aninnl  failing,  27-S. 

Tooth-Germs,  elephant,  274. 

Tooth  Germs,  human,  tiansforma- 
tioiis  of  epithelial  and  enamel 
germs,  dentine  bulbs,  caps,  &c., 
in,  from  Tth  to  39th  week,  40. 

Tooth-Tumor,  unusual  case  of,  196. 

Tooth  and  Bone,  analogy  of,  23. 

Toxodon,  remains  of,  109  ;  descrip- 
tion of,  254. 

Trephine,  the.  254. 

Trephining  Sinuses,  157-161. 

Trigeminus  Nerve  (in  the  horse),  de- 
scription of.  216-226. 

Tripier,  M..  resection  of  nerves,  217. 

Tncar.  the,  255. 

Tushes,  fighting  with,  in  various 
animals,''77-85. 

Tubes  horses',  practically  useless, 
75;  different  from  other  teeth.  75: 
distances  from  inci-ors  and  grind- 
ers, 75.  75;  shape  and  dimensions 
of,  76  ;  curvatnre  of  roots,  76. 

Tushes,  removal  of,  155. 

Tashes,  size  of  in  Orohippus,  97. 

Tusks,  elephant  fighting  with,  77; 
varying  curvatures,  v^eight,  length, 
&c.,  of.  276. 

Tuttle,  R.  M.,  on  evolution,  270-2. 

Varnell,  G.,  opinion  of,  102  ;  dis- 


eases of  teeth,  138, 139 ;  the  sinuses, 
15:i,  15.j.  101  ;  canes,  164-106;  ait- 
eases  of  alveolar  processes,  loo; 
parrot-mouth,  lOT ;  osteo-sarcoma, 
180-7;  fractured  jaws,  194. 
Views  of  an  evoluliouist,  270-2. 

Wallace.  A.  K,  cause  of  destruc- 
tion oiungulata.  111;  fossil  horses, 
112  ;  geology,  240. 

Walrus^  the,  mode  of  fighting  of,  77. 

Walsh.  J.  H.,  age  by  teeth,  zvS. 

Wedges,  scientific,  use  of.  2"il. 

West,  bone-beds  of  the,  257. 

Wheeler,  Capt.,  report  on  survey  of, 
261-2. 

Williams,  Prof.  W.,  teething,  91; 
remnant  teeth,  104,  105 ;  dental 
cysts,  125-127  ;  caries,  1C9-171. 

Williams.  W.,  necrosis,  216. 

Winter,  J.  H.,  use  of  tushes,  85. 

Wolf-teeth,  why  a  good  generic 
name,  94. 

Woodward,  J.  J.,  tooth  pulp,  31; 
histoloiry.  241. 

Woolly  Rhinoceros,  (fossil),  251. 

Works,  general,  4. 

Works,  special,  4,  290. 

Wortman.  J.  L..  on  fossil  horses, 
2.57-269;   discovery  of.  260. 

Wyman,  Prof,  discovery  of,  81. 

Yates,  L.  G.,  fossil  elephant  teeth, 
27{i. 

Youatt,  W..  sugar  as  food.  30  ; 
tooth-2:ei-ms,  44,  45 ;  infundibula 
of  grinders.  58 ;  description  of 
lower  jaw,  62  ;  use  of  tushes,  84 ; 
teething,  85.  86 ;  lampas.  90,  91 ; 
croppi:)g  horses'  ears.  103 ;  rem- 
nant teeth.  105;  food,  1C2-164 ; 
disea-^e''  of  teeth.  172,  173  ;  frac- 
tured jaws.  196-198;  'mark'  of 
central  nippers,  205;  difficulties 
of  iud"-i'Tg  age,  20'^;  bishoping, 
210";  trad"  Incks.  212,  214;  crib- 
bitine,  212,  213  ;  indications  of  aire 
in^eoendent  of  teeth.  214;  fifth 
pair 'of  nerves,  216-225;  caecum, 
230;  colon.  2.32;  membrana  nicti- 
tans.  244  :  solipeds.  253. 

Youmans,  E.  L.,  evolution,  237. 

Zebra,  temporary  canine  teeth  of, 

52. 
Zoology,  definition  of,  256. 


PUBLIC    OPINION. 


HoESES'  Teeth.— Such  is  the  title  of  a  work  we  have  just 
read  with  considerable  interest,  because  it  embraces  much  that 
is  instructive  and  useful.  Designed  as  the  publication  is  to 
^ve  a  synopsis  of  the  fundamental  principles  of  dental  science, 
it  has  a  defect  attributable  to  the  author's  lack  of  practical 
experience  in  the  specialty  of  which  he  treats.  *  *  *  The 
chapter  on  canine  teeth  contains  much  of  interest,  and  fully 
sustains  the  theory  that  horses  suffer  from  febrile  irritations, 
as  the  result  of  interrupted  dentition,  and  that  the  free  use  of 
the  lance  is  as  serviceable  as  when  used  on  an  obstructed  eye- 
tooth  of  a  child.  The  disease  known  as  lampas,  which  is  often 
accompained  by  a  distressing  cough,  and  which  so  seriously 
interferes  with  feeding,  is  shown  to  be  due  to  the  same  cause 
and  to  require  the  same  remedy.  To  state  that  caries  most 
frequently  proceeds  from  infiainmation  beginning  in  the  pulp- 
cavity,  or  that  caries  of  the  roots  is  the  result  of  inflammation 
of  the  alveolo-dental  periosteum,  is  certainly  far  from  the  ex- 
perience of  the  practical  dentist;  but,  notwithstanding  these 
defects,  there  is  much  of  value  in  this  (the  eighth  chapter)  as 
well  as  the  succeeding  chapters  on  the  dentistry  of  the  teeth, 
their  indications  of  age,  their  nerves,  &c,  *  *  *. — C.  N. 
Pierce  in  ''Dental  Cosmos." 

"Horses'  Teeth,"  by  Wm.  H.  Clarke  of  New  York,  is  a 
neat  and  handsomely  bound  volume,  containing  selections  from 
the  very  best  authors,  with  appropriate  additions  by  the 
author,  making  a  book  that  is  invaluable  to  veterinary  sur- 
geons, and  of  great  practical  benefit  to  dentists,  and  should  be 


288  PUBLIC  0Pi:s'i02^. 

studied  by  every  parson  who  treats  tlie  teeth.  The  author 
treats  of  the  teeth  from  the  time  of  the  formation  of  the  germ 
to  their  full  development,  and  gives  their  pathology  and  den- 
tistry also.  A  vocabulary  of  the  technical  terms  used  forms  a 
valuable  addition. — Dental  News. 

This  work  is  undoubtedly  in  advance  of  anything  hereto- 
fore published  on  the  subject  in  this  country.  ^'  '•"  *  When 
the  author  says  that  "  probably  the  temporary  teeth  are 
absorbed  by  the  permanent,"  he  displays  the  folly  of  attempt- 
ing to  write  on  a  subject  that  one  does  not  understand.'^  Still 
the  work  is  useful  and  will  probably  aid  in  the  elevation  of 
veterinary  surgery. — M'ss)uri  Dental  Journal. 

This  book  is  in  a  great  measure  a  compilation  from  works 
on  dentistry,  anatomy,  physiology,  microscopy  and  veterinary 
surgery,  as  they  relate  to  the  davelopment,  structure  and  care 
of  the  teeth  of  horses.  As  we  are  a  believer  in  horse  dentistry, 
we  have  looked  over  the  work  with  much  pleasure  and  no 
inconsiderable  profit. — Demal  Adverassr. 

This  book  is  a  venture  in  the  field  of  veterinary  science 
which  we  hope  to  see  more  frequently  imitated.  It  is  mainly 
a  compilation,  admirably  arranged,  and  prepared  with  great 
thoroughness  of  detail.  The  compiled  matter  is  well  selected 
and  condensed,  much  of  it  being  rewritten.  It  contains  much 
besides  the  matter  pertaining  to  horses'  teeth,  the  teeth  of 
many  other  animals  being  described  and  compared  with  those 
of  the  horse ;  in  fact,  the  work  might  be  entitled  "  Teeth " 
instead  of  -'Horses'  Teeth."  It  gives  a  history  of  the  evolu- 
tion of  the  horse  from  early  geological  periods,  the  wolf-teeth, 
which  the  author  has  named  "  Remnant  Teeth,"  being  traced 
back  to  the  Eocene  period,  when  they  were  functionally 
developed.  This  fact  throws  light  on  what  has  been  a  mys- 
tery, and  the  author  appears  to  have  made  a  discovery. 

The  work,  as  a  whole,  is  very  commendable,  and  we  feel 

*  See  pages  48  and  59.  A  few  changes  have  been  made  and  some  fresh 
matter  added.  But  I  will  venture  to  ask  the  editor  of  the  Journal  what 
becomes  of  the  I'oots  of  a  temporary  tooth  when  the  shell  of  its  crown  when 
8hed  is  sometimes  not  more  than  the  sixteenth  of  an  inch  in  thickiiessf 
Wiiat  becomes  of  the  roots  of  elephant  teeth  ?    (See  pages  2T4-5-€.) 


PUBLIC  opi^^ioi?^.  289 

sure  it  will  find  a  place  in  the  library  of  all  interested  in  a 
thorouglily  practical  as  well  as  scientific  knowledge  of  horses' 
teeth,  and  will  be  found  especially  valuable  both  to  the  student 
and  practitioner  of  comparative  medicine  and  surgery. — Jour- 
nal of  Comjparatide  Medicine  and 


The  work  consists  mainly  of  quotations  from  standard 
writers.  It  is  very  interesting  and  instructive  reading,  and  is 
fully  worth  the  small  sum  it  costs.  The  author  deserves  credit 
for  his  labor  in  collecting  information  from  so  many  separate 
sources,  and  presenting  it  in  so  small  a  compass  and  so  readable 
a  form.  However,  there  are  errors  in  the  vocabulary  that  ought 
to  be  corrected. —  Veterinary  Gazette. 

It  possesses  the  merit  of  presenting  in  a  condensed  form,  for 
the  study  of  the  veterinary  surgeon,  the  anatomy,  pathology, 
and  reparative  surgery  of  horses'  teeth,  and  to  him  it  will  save 
much  labor  and  furnish  a  ready  reference,  and  hence  be  an 
eflacient  aid.     *    *    *— Medical  Gazette, 

*  *  *  The  work  contains  an  immense  amount  of  useful 
information,  and  as  it  fills  an  unoccupied  field,  ought  to  be 
successful. — Medical  Record. 

We  understand  this  book  is  having  a  rapid  sale  among 
horsemen.  Hereafter  we  suppose  the  title  H.  D.  D.  will  be- 
come common.  How  nicely  Mr.  Clarke  tells  us  of  the  cutting 
and  shedding  of  the  temporary  and  permanent  dentitions.  In 
the  future  we  expect  that  greater  attention  will  be  given  to  the 
i&idih..— North  American  Journal  of  Homeopathy. 

Horses'  Teeth. — Owners  of  all  classes  of  horses  should  be 
in  possession  of  a  remarkably  useful  work  entitled  "  Horses' 
Teeth,"  by  Wm.  H.  Clarke.  The  work  is  based  on  the  best 
authorities  on  odontology  and  veterinary  science,  and  arranged 
in  an  easy,  comprehensive  form.  With  a  view  of  rendering 
technical  terms  readily  understood,  a  vocabulary  of  the  medical 
and  technical  terms  is  attached.  Dental  science,  as  hitherto 
expounded,  has  never  afforded  horse  owners  the  instruction  it 
professes  to  aim  at.  The  trouble  has  been  the  use  of  technical 
phrases.  Mr.  Clarke,  alive  to  the  necessity  of  giving  to  the 
imblic  a  popular  treatise,  has  presented  a  work  which  must 


290-  PUBLIC   OPIis^IOK. 

find  its  way  in  all  circles,  and,  above  all,  reach  tlie  understand- 
ing of  the  average  reader. — Turf,  Field  and  Farm. 

This  work  deals  with  horses'  teeth  in  a  very  complete  man- 
ner, and  vv'iil  doubtless  be  found  of  great  value  by  students  of 
veterinary  science.  It  is  a  compilation,  but  Mr.  Clarke  has  done 
his  work  in  a  careful  manner.  *  *  *  A  study  of  this  work 
cannot  fail  to  be  of  value  to  all  who  are  interested  in  the 
horse. — London  {Eng.)  Live  Stock  Journal. 

The  book  is  compiled  from  the  best  authorities. — Rural 
New  'Yorker. 

Horses'  Teeth. — We  have  received  from  Mr.  W.  H.  Clarke 
a  duodecimo  volume  containing  a  compilation  of  everything 
valuable  that  has  been  written  by  the  best  known  odontologists. 
*  vt  *  -pi^g  so-called  "  wolf-teeth  "  are  traced  to  the  horse 
which  existed  previous  to  the  pliocene  period.  Mr.  Clarke 
calls  them  "  remnant"  teeth.  *  *  *  The  work  is  a  valuable 
addition  to  veterinary  science. — The  Country  Gentleman. 

It  is  a  venture  in  the  field  of  veterinary  science,  and,  though 
in  general  a  compilation,  will  be  found  of  great  practical  service, 
and  in  its  present  form  a  new  thing.  It  will  be  of  use  especially 
to  horsemen  and  farmers. — Massachusetts  Ploughman. 

This  work  is  mainly  compiled,  but  the  selections  evince  care, 
judgment,  resoarch,  and  discrimination.  It  will  prove  valuable 
to  the  veterinary  student  and  practitioner. — Pen  and  Plow. 

Had  this  work  been  issued  prior  to  Huxley's  "  Crayfish"  or 
Comtc's  "  Sight "  it  would  have  been  deemed  too  special.  The 
subject  is  scientifically  treated,  with  a  decided  tendency  toward 
the  practical.     *    *    *. — Syracuse  Standard. 

Horses'  Teeth. — *  '^  *  Mr.  Clarke  devotes  considerable 
space  to  descriptions  of  the  different  classes  of  teeth.  *  ^  * 
Although  there  is  a  ^reat  deal  of  technical  language  in  the 
work  the  copious  vocabulary  at  its  close  renders  it  practical  for 
those  who  wish  to  learn  about  the  structure  and  dissases  of  the 
teeth,  and  the  method  of  treating  them  under  various  circum- 
stances. Many  instances  are  quoted  from  good  authorities  in 
which  horses  have  been  treated  for  diseases  of  the  jaw,  and  the 


PUBLIC   OPINION".  291 

metliods  by  means  of  wliicli  they  were  cured  are  carefully  set 
foitli.  We  present  som3  extracts  from  the  chapter  on  ihe  teeth 
as  indicators  of  age.  (See  pp.  204-5.)  The  treatment  of  this 
subject  is  only  an  example  of  the  fullness  and  accuracy  of  the 
entire  work. —  Utica  Her  old, 

Mr.  W.  H.  Clarke's  "Horses'  Teeth"  is  a  complete  and 
interesting  treatise  which  may  be  accepted  at  once  as  both  a 
useful  manual  of  equine  dentistry  and  an  aorreeable  study  of 
certain  aspects  of  comparative  zoology.  Every  possible  de- 
formity or  peculiarity  observable  in  the  teeth  of  the  horse,  as 
well  as  every  ro^ruery  practiced  on  them  by  dishonest  dealers 
is  fully  handled,  and  a  succinct  account  is  given  of  all  the 
maladies  of  the  teeth  themselves,  and  of  other  organs  with 
which  the  teeth  have  a  functional  relation. — New  York  Herald. 

The  treatise  on  horses'  teeth  by  William  H.  Clarke,  a  metro- 
politan journalist,  has  already  attracted  wide  attention,  and  is 
an  invaluable  work  in  its  way.  Great  care  and  much  labor 
have  been  bestowed  in  its  preparation,  and  the  book  supplies  a 
want  that  has  long  been  felt  by  horsemen,  farmers  and  the 
student  and  practitioner  of  comparative  medicine  and  surgery. 
— New  York  Gra'phk. 

The  title  so  fully  describes  the  scope  of  the  volume  that 
little  need  be  added  except  criticism.  The  author  is  frank 
enough  to  admit  professional  inexperience,  but  has  made  the 
topic  of  the  work  a  matter  of  careful  investigation  for  a  year. 
He  has  wisely  deferred  to  the  opinions  of  naturalists  and  veter- 
inary surgeons,  and  quotes  liberally  from  their  works  in  every 
chapter,  thus  supplying  a  cyclopedic  stock  of  information  bear- 
ing directly  on  horses'  teeth  in  health  and  disease,  which  is 
very  convenient  for  those  who  keep  or  raise  horses,  and  the 
average  veterinary  surgeon. — PhrerKjlogical  Journal. 

The  thoroughness  of  detail  with  which  every  point  relatincr 
to  the  subject  of  this  work  is  treated  will  impress  every  one 
with  its  reliability  and  value.  It  is  undoubtedly  true  that 
much  suffering,  disease  and  death  have  resulted  from  ignor- 
ance of  what  is  herein  given,  and  that  much  unintentional 
cruelty  to  horses  may  be  prevented  by  studying  this  vol»me. 


293  PUBLIC   OPINION. 

Tliougli  tlie  ti'le  implies  that  the  work  is  confined  exclusively 
to  the  teeth  of  horses,  it  is  not  so  ;  the  teeth  of  other  animals 
claim  nearly  as  much  attention  as  those  of  the  horse.  The 
theory  of  evolution  is  introduced,  the  history  of  the  horse  being 
traced  from  the  Eocene  period,  when  the  wolf  or  "remnant" 
teeth  were  functionally  developed.  The  book  will  be  prized  by 
all  who  seek  the  welfare  and  happiness  not  only  of  the  human 
race,  but  of  all  sentient  beings. — Banner  of  Light. 

We  all  know  that  horses  suffer  with  their  teeth,  and  the 
work  gives  full  instructions  as  to  their  care.  *  *  *  The 
author  is  an  evolutionist,  and  has  devoted  much  study  to  fossil 
horses. — Neio  Orleans  Times. 

Peactical  Books, — "  Horses'  Teeth,"  is  a  valuable  treatise 
that  ought  to  be  in  the  possession  of  horsemen,  farmers,  and 
veterinarians.     ^    *    *. — Pittsburg  Commercial  Gazette. 

Dr.  C.  F.  Hoeing  (Jersey  City  Hights,  N.  J.)  says :  "  After 
a  careful  reading  of  your  book,  *  Horses'  Teeth,'  I  wish  to  say 
that  it  appears  to  me  to  be  an  able  compilation  of  scientific 
farjts,  and  a  basis  for  further  investigation  of  horse  dentistry 
by  the  profession;  at  the  same  time  containing  valuable  in- 
formation for  intelligent  horsemen  and  farmers,  as  well  as 
naturalists  generally.  I  miss  only  very  valuable  information 
to  be  found  in  numerous  German  books." 

Dr.  J.  M.  Heard,  205  Lexington  Ave.,  New  York,  says  : 
"  The  book  is  full  of  valuable  information  ;  in  fact,  one  would 
search  a  single  library  in  vain  to  obtain  it.  None  but  those 
who  have  performed  similar  work  can  appreciate  the  immense 
amount  of  labor  expended  in  its  preparation.  No  student  or 
practitioner  can  afford  to  be  without  it." 

Dr.  B  ?.  Brewster  of  Norwich,  Conn.,  says  :  "  I  have  been 
an  advocate  of  horse  dentistry  for  thirty  years,  even  arguing 
against  veterinary  surgeons.  Thank  God,  light  has  come  at 
last." 


l-Year-OId.  Lower  Jaw  (Brandt). 


2- Year-Old,  Lower  Jaw ;  drawn  from  Nature. 


3-Year-OId,  Lower  Jaw ;   drawn  from  Nature. 


5-Year-Old,  Lower  Jaw ;  drawn  from  Nature. 


5- Year-Old,  Lower  Jaw ;  drawn  from  Nature. 


7- Year-Old,  Lower  Jaw  (Brandt), 


8- Year-Old,  Fpper  Jaw  (Walsh).    About  %  nat  size. 


10-Year-Old,  Upper  Jaw  (Walsh),    About  H  nat.  size. 


'^mi 


11  years,  Upper  Jaw.     The  marks  have  disappeared. 


The  Mark,  dissected  as  it 
were.     (See  page  58.) 


<5,  The  Dentinal  star,  some* 
times  mistaken  for  the 
mark.     (See  page  209.) 


12  years,  Lower  Jaw.  Change  in  shape  is  now  clearly  defined. 
The  respective  pairs  (centrals,  dividers,  corners)  assume  in  turn 
(from  13  years  till  old  age)  various  shapes— semi-square,  rounded, 
triangular,  wedge-shaped,  etc. 


13  years,  Lower  Jaw. 


14  years,  Lower  Jaw. 


15  years,  Upper  Jaw. 


16  years,  Upper  Jaw, 


17  years,  Upper  Jaw. 


18  years,  Lower  Jaw. 


19  years.  Lower  Jaw. 


20  years,  Lower  Jaw. 


21  years,  Upper  Jaw. 


S^^: 


23  years,  Upper  Jaw. 


23  years,  Upper  Jaw. 


24  years,  Lower  Jaw, 


25  years,  Lpwer  Jaw, 


26  years,  Lower  Jaw. 


27  years,  Upper  Jaw. 


28  years,  Upper  Jaw. 


29  years,  Upper  Jaw. 


A  Parrot-Mouth  (lower  jaw).  The  ten  lines  represent  ten 
years'  growth.  The  marks,  having  never  been  worn,  represent 
a  6-year.old.  The  horse  is  therefore  16  years  old.  (This  cut, 
as  well  as  many  of  the  preceding,  is  from  Brandt's  "Age  of 
Horses,") 


DPLj^TE    IV. 

26  27 


John  IRe^nbers  &  Co., 


MANUFACTURERS  AND  IMPORTERS  OF 

f  BtfriDsni  ^nstrnnipnte 

OF  SUPERIOR  QUALITY  AND  WORKMANSHIP. 

Slings  for  Suspcnbing  Hnimals 

A     S  PE  C  I  ALT  Y. 

mo.  303  ifourtb  Hvenue, 

Vuvo  Dorf. 


Price    List    of   Veterinary    Dental    Instruments 
Illustrated  in  this  book. 

Plate   J.      Fig.  1.  Adjustable  Tooth  File  ;   in  handle  to  unscrew,  $4.00 

"    2.            "             "          "       in  stiff  handle '.  3.00 

House's         "          "       in  handle  to  unscrew,  4.00* 

House's          "          "       in  stiff  handle 3.00* 

"               "    3.  Prof.  Going's  Tooth  Chisel 17.50 

••               "    4.  French  Model      "           "        14-00 

"               "    5.  Tooth  Mallet,  lead  filled,  not  rebounding 2.50 

'♦               "    6.  French  Model  Tooth  Saw 3.50 

••              "    7.  Narrow  Tooth  Chisel,  length  5  inches 1-25 


Plate   I.     Fig.  8.  Narrow  Tooth  Gouge,  length  5  inches $1.30 

"               "    9.  Tooth  Rasp  guarded  ;  in  stiff  handle 3.00* 

"        "           "           in  handle  to  unscrew....  3.75* 

"        "      plain  ;  in  stiff  handle 1.75* 

"        "      plain  ;  in  handle  to  unscrew 2.50* 

"               "  10.  Extra  Blade  for  Adjustable  Tooth  File 0.40 

Extra  Blade  for  House's          "        "     0.40* 

Plate  U.        "  11.  Heavy  Tooth  Forceps,  length  15  inches 5.50 

"  "  12.  Prof.  Going's  Tooth  Forceps  with  closing  screw 

and  crank  handle 25.00 

"  "  13.  House's  Tooth  Cutting  Forceps,  i 

"               "  14.  House's  Tooth  Pulling  Forceps,                          y  28.00 
one  set  of  removable  handles  to  both  j 

••               "  15.  Wolf  Tooth  Forceps,  length  9  inches 3.50 

"               •'  16.  Wide  Tooth  Chisel,  length  10  inches 2.00 

"       16      "        3.00 

Plate  IIL      "  17.  Tooth  Cutting  Forceps,  French  model 25.00 

«               "18.       "           "             "          MoUer's...., 32.00 

"19.       "           "             "          French  model 20.50 

••                "  20.  House's  Tooth  Cutting  Forceps 6.50 

"                ••21.         "            "            "                "         6.50 

"                "22.        "            "            "                "         6.50 

M                "23.         "            "            "                "         6.50 

**                "  24.  Narrow  Tooth  Gouge,  with  steel  head 2.00 

Plate  ir.      "  25.  Bow  Tooth  Saw,  with  two  blades 6.00 

"               "  26.  Tooth  Key,  with  hoolis  of  assorted  sizes 35.00 

"  27.  Plain  Tooth  Saw 1.50 

"  28.  Chain  Tooth  Saw 12.50 

•<               "  29.  Fine  ferruled  Tooth  Saw 1.75 

••                "  30.  Narrow  Tooth  Chisel,  length  6  inches 1.25 

"  31.  Hurlburt's  Gum  Knife  and  Tooth  Pick  2.00 


Our  Alphabetical  Register  of  Veterinary  In- 
struments of  90  Pages  and  containing  about  325 
engravings,  mailed  free  upon  receipt  of  four  Cents 
for  Postage,  to  all  who  mention  this  book. 


COLUMBIA  VETERINARY  COLLEGE 


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THE 

REGULAR  TERMS  OPEN  IN  OCTOBER. 

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TURF,  FIELD  AND  FARM 

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TURF,    FIELD   AND   FARM 

Has  won  the  patronage  of  the  very  best  and  most  intelligent 
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